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EXPLANATION OF PLATE I. 

[Figures 1 to 8, inclusive, natural size.] 



Gypsy Moth, Porthetria dispar (L.). 



Fig. i. Female with the wings spread. 

2. Female with the wings folded. 

3. Male with the wings spread. 

4. Male with the wings folded. 

5. Pupa. 

6. Caterpillar. 



Full grown. 

7. Caterpillar. 

8. Cluster of eggs on bark. 

9. Several eggs enlarged. 

10. One egg greatly enlarged. 



Plate I 




.1 









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#3 A 







Drawn by Joseph Bridgham 



Geo.H.'Walker &Co.,Boston. 



GYPSY MOTH. 



The Gypsy Moth. 

PORTHETRIA DISPAR (LlNN.). 



A Report of the Work 

of destroying the insect in the commonwealth of 

Massachusetts, together with an Account 

of its History and Habits both in 

Massachusetts and Europe. 



By 

Edward H. Forbush, 

Field Director in Charge of the Work of destroying the Gypst Moth, 

Ornithologist to the State Board of Agriculture, former 

President of the Worcester Natural 

History Society, etc., 



Charles H. Fbrnald, A.M., Ph.D., 

Professor of Zoology in the Massachusetts Agricultural College, 
Entomologist to the State Board of Agriculture, 
Entomologist to the Hatch Experi- 
ment Station, etc. 



Published under the direction of the State Board of Agriculture 
by authority of the legislature. 



BOSTON : 

WRIGHT & POTTER PRINTING CO., STATE PRINTERS, 

18 Post Office Square. 

1896. 



387270 
•29 



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LETTER OF SUBMITTAL. 



Boston, Jan. 1, 1896. 
To the Massachusetts State Board of Agriculture. 

Gentlemen : — We have the honor to submit herewith 
the report on the gypsy moth, which has been prepared 
under our direction, as authorized by chapter 71, Resolves 
of 1894. 

Respectfully, 

E. W. WOOD, 
AUGUSTUS PRATT, 

F. W. SARGENT, 
J. G. AVERY, 

S. S. STETSON, 
WM. R. SESSIONS, 

Committee on the Gypsy Moth. 



CONTENTS. 



Page 

Prkface, ix 

The Gypsy Moth, Porthetria dispar (L.). 
Part I., E. H. Forbush. 

The gypsy moth : its history in America, 3 

Its introduction, 3 

The unnoticed increase of the moth, 4 

Influences that at first retarded its increase, 5 

The first destructive appearance of the moth, 7 

The outbreak of 1889 10 

The swarming caterpillars become a serious nuisance 14 

The destructiveness of the moth, 23 

How the people fought the moth, 28 

The matter brought to the attention of the public at large, .... 32 

The commission of 1890, 38 

The work of 1891 45 

The work of 1892, 62 

The work of 1893, 68 

The work of 1894, 72 

The work of 1895 83 

The number of men employed and work done, 1890 to 1894 inclusive, . . 89 

The increase and distribution of the gypsy moth, ' 94 

The rate of increase, 94 

Distribution as affected by food supply and other natural causes, . . 97 

The connection of distribution and population, 99 

The distribution of the moth by man's agency, 100 

A study of the methods and routes of transportation, 106 

The effect of the work of extermination on the distribution of the gypsy 

moth, 113 

Methods used for destroying the gypsy moth, . 117 

The destruction of the eggs, 117 

The destruction of the caterpillars, 126 

Measures for destroying all forms of the moth, 164 

A summary of the methods most useful to the farmer, .... 194 

The annual inspection, 196 

Measures for the information of the public, 198 

Natural enemies of the gypsy moth, 203 

Insect-eating birds, 203 

Birds seen to feed upon the gypsy moth, 207 

The progress of extermination, 244 

The Gypsy Moth, Porthetria dispar (L.). 
Part II., C. H. Fernald. 

Scientific and common names, 255 

Bibliography, 257 

Distribution in other countries, 267 

The gypsy moth in England, 268 

Injuries in the old world, 273 

Methods of destroying the gypsy moth in Europe, 284 



viii CONTENTS. 

Page 

The eggs, 288 

Scattered eggs, • <KW 

Date of hatching, 294 

A second brood, 295 

The larva or caterpillar, 299 

Feeding habits, 311 

Process of pupation, 332 

The pupa, 333 

Pupation in the field, 335 



The imago, 



336 



Mating, 342 

Habits of flight, 344 

The assembling of the gypsy moth, 345 

On trapping males, 357 

Oviposition, 363 

Parthenogenesis 365 

Internal anatomy, 368 

Natural enemies of the gypsy moth, 375 

Hymenoptera, 375 

Coleoptera, 381 

Diptera, 385 

Hemiptera, 392 

Spiders, 404 

Insectivorous vertebrates, 404 

Vegetable parasites, 405 

Insecticides, 407 

• Analyses of poisoned larva? 474 

Effects of insecticides on foliage 489 

Analyses of insecticides, 492 

Leaf area of trees, 494 

Appendices : — 

Appendix A, report of a conference held at the rooms of the State Board of 

Agriculture, Boston, Mass., March 4, 1891, iii 

Appendix B, revised rules and regulations adopted by the State Board of 

Agriculture, xx 

Appendix C, an extract from a description of Section 8, Medford, as it appears 
in the section book, showing the condition of that section and the 

work done in it in 1891, xxvii 

Appendix D, reports of entomologists who visited the infested region in 1893, xxxii 

Appendix E, reports of entomologists who visited the infested region in 1894 ; 

opinion of the United States entomologist, xliii 

Appendix F, the dangers of arsenical poisoning resulting from spraying with 

insecticides, Hi 

Appendix G, a list of correspondents and observers who have furnished in- 
formation in regard to the gypsy moth in Massachusetts, . . . lviii 



PREFACE. 



This report is respectfully submitted for the benefit of 
the people of Massachusetts, especially those residing in 
the district infested by the gypsy moth, who have suffered 
from the injuries inflicted by the insect. The design of the 
report is to present, within the prescribed limits, as full a 
history as possible of what is known about the gypsy moth 
in Massachusetts ; also to give a brief resuiM of its history 
abroad. We have endeavored to present most fully those 
features of the subject which are most important from a 
practical and economic standpoint. That clause in chapter 
71 of the Resolves of 1894 which authorizes the prepara- 
tion for printing "of the scientific facts ascertained" has 
been kept in view, and much matter of a more or less scien- 
tific or technical nature, which has come under our notice in 
connection with the field work or while making the inves- 
tigations and experiments with which we have been charged, 
has been recorded in this volume. The investigations of 
the life history and habits of many of those forms of animal 
life which exert controlling influences upon the gypsy moth 
have not yet proceeded far enough to allow the results to be 
fully chronicled. A summary of the results of some of the 
most important experiments is given, and, where observa- 
tions have been made by a sufficient number of individuals 
to warrant the drawing of conclusions, such conclusions 
have been recorded. A further study of the parasites and 
enemies of the gypsy moth is in progress. 

Part I. of this volume records such of the most impor- 



x PREFACE. 

tant results attained by the State Board of Agriculture in 
the work of exterminating the gypsy moth as could be in- 
cluded within the limits of the space allowed to the report. 
Part II., besides giving the bibliography of the moth and 
instances of its injuries in Europe, deals especially with the 
"scientific facts ascertained," and chronicles many of the 
more important experiments made with a view of finding 
means to check the ravages of the insect and secure its 
extermination. 

The authors are well aware of many shortcomings in the 
work. They have labored under the disadvantage of resid- 
ing in different parts of the State, and therefore have not 
had opportunity to consult together and compare notes as 
often as was desirable. All responsibility for error in 
either part will be assumed individually by the author to 
whom that part is accredited. Other duties which were 
imperative in their demands upon our capacity for labor 
have at times prevented that painstaking revision which 
such work requires. Much valuable information has neces- 
sarily been excluded for lack of space. It was impossible, 
for instance, to quote fully from accounts of injuries com- 
mitted by the moth in Europe. For the same reason, one 
hundred and forty-six statements in regard to the ravages 
of the moth, from residents of the infested district in Mas- 
sachusetts, have been omitted. Extracts from some of them 
are given, however, in Part I. Most of that portion of 
Part I. which is devoted to spraying was prepared in 1894, 
and cannot be considered as up to date, as spraying has not 
been one of the chief methods employed in the field work 
of the last two years. 

The Appendices relate largely to the views expressed by 
certain eminent entomologists in regard to the work of ex- 
termination. Appendix F, on the dangers attendant on 



PREFACE. xi 

arsenical poisoning by spraying, was written by Mr. For- 
bush. 

The drawings for the insect plates were made by Mr. 
Joseph Bridgham, Miss Ella M. Palmer and Mr. J. H. 
Emerton. The drawings of appliances and tools were made 
by Mr. C. A. King. Messrs. A. H. Kirkland, R. A. Cooley 
and C. P. Lounsbury made the drawings for the anatomical 
plates. Most of the other drawings were made by Mr. 
Kirkland. 

We are under obligations to the Boston Woven Hose and 
Rubber Company, W. & B. Douglass, Gould Manufacturing 
Company, A. H. Nixon and John J. McGowen for cuts 
of spraying apparatus ; also to Estes & Lauriat for three 
cuts from " Coues' Key to North American Birds," Little, 
Brown & Company for three cuts from Baird, Brewer and 
Ridgway's " North American Birds," and J. B. Lippincott 
for two cuts from " Birds About Us," by Dr. C. C. Abbott. 

It only remains to perform the pleasant duty of acknowl- 
edging the many favors which have been bestowed upon us 
by those who have assisted in the preparation of this work. 
Acknowledgments are due to the scores of foreign corre- 
spondents, both eminent naturalists and government officials, 
who have furnished information, and also to residents of 
the infested district, who have given useful information, 
and whose names appear in Appendix G. In our biblio- 
graphical researches we have been most courteously and ably 
assisted by the officials of the Boston Public Library and 
those of the libraries of Harvard University, Museum of 
Comparative Zoology, Arnold Arboretum, Boston Society 
of Natural History, Boston Athenaeum, Massachusetts Horti- 
cultural Society and Massachusetts Agricultural College. 
To Mr. Samuel Henshaw we are especially indebted for 
assistance in obtaining many references concerning the 



xii PREFACE. 

history of the gypsy moth in Europe ; and to Dr. F. B. 
Stephenson, U. S. N., for the translation of Russian works. 

We are greatly indebted to Messrs. J. A. Farley and A. 
H. Kirkland for very valuable services in connection with 
the preparation of the report. Mr. Farley, who has made an 
exhaustive study of the distribution of the gypsy moth, has 
contributed the material for that portion of the paper on 
distribution which treats of the ' ' methods and routes of 
transportation." While certain portions of Part II. are 
credited in the text to Mr. Kirkland, he has been of great 
assistance to the authors in many other ways. Messrs. F. 
H. Jones, F. A. Bates and C. W. Minott have rendered 
much aid in the way of criticism and suggestion. Lack of 
space forbids the mention by name of the scores and even 
hundreds of other intelligent observers, more or less per- 
manently connected with the work, who have furnished use- 
ful notes. 

The main credit for the production of this volume is due 
to the committee of the State Board of Agriculture, who 
have for live years conducted the work with the steadfast 
purpose of ridding the Commonwealth of the gypsy moth. 
They have recommended that the Legislature authorize the 
preparation and printing of the report. They have con- 
ferred upon us the honor of preparing the volume, and our 
thanks are due to them for endorsement of our plans and 
for their constant and consistent support. 

THE AUTHORS. 



THE GYPSY MOTH 

POKTHETRIA DISPAE (L.) . 

Part I. 

IE. ZE3I. FOEBUSH. 




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The Gypsy Moth 

Its History in America. 



Its Introduction. 

The gypsy moth.(Porthetria dispar)& pest of European 
countries, was introduced into America in 1868 or 1869 
by Leopold Trouvelot, a French artist, naturalist and astron- 
omer of note. Prof. C. V. Riley, then State entomologist 
of Missouri, recorded the occurrence in 1870 in these words : 
" Only a year ago the larva of a certain owlet moth (Hy- 
pogymna dispar) which is a great pest in Europe both to 
fruit trees and forest trees, was accidentally introduced by a 
Massachusetts entomologist into New England, where it is 
spreading with great rapidity." * 

Though Professor Riley did not then mention Trouvelot 
or Medford, the facts were evidently well known to him, as 
twenty years later he wrote in "Insect Life" as follows: 
"This conspicuous insect, although not recorded in any of 
our check lists of North American Lepidoptera, has un- 
doubtedly been present in a restricted locality in Massachu- 
setts for about twenty years. It was imported by Mr. L. 
Trouvelot in the course of his experiments with silk-worms, 
recorded in the early volumes of the ' American Naturalist,' 
and certain of the moths escaping, he announced the fact 
publicly, and we mentioned it in the second volume of the 
'American Entomologist,' page 111 (1870), and in our 
' Second Report on the Insects of Missouri,' page 10." f 

In a Bulletin of the Hatch Experiment Station, published 
in November, 1889, Prof. C. H. Fernald wrote: "Mr. 
Samuel Henshaw and Dr. Hagen of Cambridge have both 
informed me that the entomologist who introduced this 

* Riley's Second Report on Insects of Missouri, page 10. 
t Insect Life, Vol. II., No. 7, 8, page 208. 



4 THE GYPSY MOTH. 

insect was Mr. L. Trouvelot, now living in Paris, but at 
that time living near Glenwood, Medford, where he at- 
tempted some experiments in raising silk from our native 
silk-worms, and also introduced European species for the 
same purpose. Dr. Hagen told me that he distinctly remem- 
bered hearing Mr. Trouvelot tell how they escaped from 
him after he had imported them." 

Prof. N. S. Shaler of Harvard University, who knew Mr. 
Trouvelot, has also stated to the writer that he remembers 
hearing Mr. Trouvelot speak of the importation and escape. 
Thus we have evidence from eminent scientific authorities 
that settles beyond doubt the approximate time and the place 
of introduction of this insect, and who was responsible for it. 
During his sojourn in Medford Mr. Trouvelot lived in a 
house (now known as No. 27 Myrtle Street) near Glenwood 
station on the Medford branch of the Boston & Maine Kail- 
road. It is said by people who lived in the vicinity in 1869 
that he imported some insects' eggs about that time, some 
of which were blown out of a window of the room in which 
they were kept, and that he was much disturbed on being 
unable to find them. Others state that the insects escaped 
in the larval form. Probably the insect was imported in the 
egg. Its escape seems to have been accidental, and Trou- 
velot, being aware of the dangerous character of the pest, 
and finding his efforts for its eradication futile, gave public 
notice of the fact that the moth had escaped from his custody. 

The Unnoticed Increase of the Moth. 

The historian is considerably embarrassed by lack of evi- 
dence in regard to the increase and spread of the moth dur- 
ing the first ten years. No one except Trouvelot is known 
to have observed it during any portion of that time. For 
most of the evidence of its spread and ravages during the 
decade from 1879 to 1889 we must depend on the testimony 
of residents of Medford and Maiden. Much information 
bearing on the subject has been obtained during the past 
three years, letters and carefully revised statements having 
been received from a large number of people in these cities. 

For several years after the moth escaped, it attracted no 
attention in Medford. People who witnessed in 1889 the 



ITS INCREASE RETARDED. 5 

first extensive outbreak of the moth in Medford, and thus 
became acquainted with its voracity and reproductive pow- 
ers, were unable to understand how so destructive a creat- 
ure could have existed unnoticed for twenty years. But 
the moth was not unnoticed after the first ten years, al- 
though its identity remained unknown and its spreading 
attracted no attention outside the locality where it was first 
introduced. Within twelve years from the time of its 
introduction it had become a serious nuisance to those 
living in and near the Trouvelot house ; but they then sup- 
posed the caterpillar to be a native. Its lack of conspicuous 
markings, which to the common eye would distinguish it 
from other species, and its habits of concealment and night- 
feeding will explain its unheeded distribution. Within 
twenty years it had spread into thirty townships and gained 
a foothold in each without attracting public attention. Of 
these facts we have the most convincing proofs. 

Influences that at first retarded its Increase. 

A study of the growth of many isolated moth colonies 
which have been found existing under conditions similar to 
those influencing the Trouvelot colony, gives abundant proof 
that the growth of such swarms for the first few years is ex- 
ceedingly slow. 

The experiments made have not yet shown conclusively 
how much the enforced and continuous inbreeding which re- 
sults from isolation affects the vitality of the species. Field 
observations show that in some cases isolated colonies have 
come very near extinction in the first years of their exist- 
ence, while others have died out. During the eight or ten 
years following its introduction, the moth, while becoming 
acclimated, battled against the many influences which served 
at first to hold it in check. A consideration of the oper- 
ation of these influences will go far toward explaining its 
apparently slow increase during the first few years. It must 
be considered that the new-comer had much to contend 
against. It had to encounter : — 

1. A new and changeable climate. How potent were cli- 
matic influences in controlling the increase of the species? 
Such influences may have been felt for years. If the moth 



6 THE GYPSY MOTH. 

was introduced from France, our harsher climate may have 
destroyed rnany of the smaller caterpillars before they had 
attained strength enough to resist exposure to its sudden 
changes. A warm period early in the season, followed by a 
cold storm or severe frost, sometimes destroys many of the 
young caterpillars. They are first hatched by the unsea- 
sonable warmth, and then killed by the cold immediately 
following. 

2. Isolation, with all its attendant perils. The isolation 
of the species and its small numbers rendered it peculiarly 
sensitive to the attacks of new enemies which surrounded it. 
Parasitic and predaceous insects were no doubt plentiful 
then, as they are to-day. The topography of the locality 
and the vegetation of the neighborhood were such as to ren- 
der it specially attractive as a breeding ground for insect- 
eating birds. Myrtle Street was then flanked by gardens 
and orchards, and nearly surrounded by woodland and bushy 
pasture. Not far to the east is a small swamp and stream, 
and the whole locality lies near the marshy banks of the 
Mystic River. Many of the birds which frequent such places 
feed on the gypsy moth in one or more of its forms wher- 
ever it is found. It is related in Samuels's " Birds of New 
England," published in 1870, that Mr. Trouvelot, who was 
then engaged in rearing silk-worms, placed two thousand of 
them on a small oak in front of his house, and that in a few 
days they were all eaten by robins and catbirds. He had a 
large area of woodland fenced in and covered with netting 
to protect his silk-worms. The birds came from all quarters 
to feed on the worms, breaking through the netting, so 
that he was obliged to shoot them in defence of his * ' infant 
industry."* Mr. Trouvelot, in describing his work on the 
American silk-worm (Telea polyphemus) , says that it is 
probable that ninety-five out of a hundred worms become 
the prey of birds. f 

At that time the cuckoos, blue-jays, orioles, vireos, cat- 
birds, bluebirds and warblers which are known to feed upon 
the caterpillars were also abundant in that locality during 
the season when the caterpillars were feeding. The inroads 

* Birds of New England, page 156. t American Naturalist, Vol. I., page 89. 



ITS EARLY HISTORY. 7 

made at first by birds alone on the comparatively small num- 
ber of caterpillars would have been sufficient to hold them in 
check. Fly-catchers secure many of the moths also ; other 
birds destroy the pupse. The restraining influence exerted 
by birds and predaceous insects would be greater in propor- 
tion when the moths were comparatively few. 

3. Forest or brush fires. The locality in which the moth 
was first liberated was favorable for its unnoticed increase 
and spread, as there were many forest trees and a dense 
undergrowth in the vicinity, which afforded it a liberal food 
supply. Undoubtedly it was somewhat checked in this waste 
land during the first few years by fires, which frequently oc- 
curred in the woodland near the Trouvelot house. Such 
fires destroy some eggs of the moth which are deposited near 
the ground, and arc also very destructive in the spring to the 
young larv?e. Mr. John Crowley, formerly one of the select- 
men of Medford, speaks of these fires as follows : — 

Glenwood, twenty-one years ago, was a thinly settled district 
and consisted largely of brush land. There were brush fires there 
every year. The fire department was called out twice in one year 
because dwellings were in danger. I think the frequent brush 
fires held the moth in check for many years, and will explain why 
they were so slow in making their appearance in the orchard and 
shade trees of other sections. 

The First Destructive Appearance of the Moth. 

After the first ten or twelve years following their intro- 
duction the moths increased so rapidly that the larva3 did 
considerable damage in the immediate vicinity of Mr. 
Trouvelot's house, according to testimony of people in the 
neighborhood. During the first few years of their abun- 
dance the insects spread along Myrtle Street and into the 
woodland and swamp at the south, across the railroad, but 
did not for some years become numerous or destructive north 
of the street. 

That the moth did not increase faster and spread more 
rapidly to other parts of Medford is largely due to the efforts 
of certain residents of Myrtle Street, who for ten or twelve 
years persistently fought the pest on their own property. 



8 THE GYPSY MOTH. 

That their efforts were finally without avail is true, but it 
might have been otherwise had the moths not remained 
unmolested in the woodland near by, from which, whenever 
food became insufficient, they sallied out and overwhelmed 
the near gardens and orchards. 

Mr. William Taylor, No. 19 Myrtle Street, speaking of 
the years from 1879 to 1889, said : — 

In the fall of 1879 I moved to 27 Myrtle Street, where Mr. 
Trouvelot, who brought the gypsy moth to this country, formerly 
lived. In the following spring I found the shed in the rear of his 
house swarming with caterpillars. I knew that Mr. Trouvelot 
had been experimenting with silk-worms, but I did not know that 
the swarms of caterpillars in the shed came from the gypsy moth. 
The caterpillars were such a nuisance in and around the shed that 
I got permission to sell it, and it was taken to Mr. Harmon's on 
Spring Street. This will explain how the moth was carried into 
that section, and why the woods there became so badly infested. 
I fought the caterpillars of the gypsy moth for ten years before 
the State did anything. In their season I used to gather them 
literally by the quart before going to work in the morning. 

Mr. and Mrs. William Belcher, well-known residents cf 
Glenwood, still residing at No. 29 Myrtle Street, have had 
the best of opportunities to observe the increase of the in- 
sect in that vicinity. Mrs. Belcher writes as follows : — 

Mr. Trouvelot, who is said to have introduced the gypsy moth 
into this country, was a next-door neighbor of ours. The cater- 
pillars troubled us for six or eight years before they attained to 
their greatest destructiveness. This was in 1889. They were all 
over the outside of the house, as well as the trees. All the foli- 
age was eaten off our trees, the apples being attacked first and the 
pears next. 

Mrs. J. W. Flinn of Maiden, who lived in Glenwood near 
Mr. Trouvelot's house during a part of this decade, says : — 

We moved to Myrtle Street, Medford, in 1882, and that year the 
gypsy-moth caterpillars were very troublesome in our yard and in 
those of our immediate neighbors. At that time they were con- 
fined to our part of Myrtle Street, but they soon spread in all 
directions. The caterpillars were over everything in our yard and 



ITS FIRST RAVAGES. 9 

stripped all our fruit trees, taking the apple trees first and then 
the pears. There was a beautiful maple on the street in front of 
the next house, and all its leaves were eaten by the caterpillars. 
They got from the ground upon the house and blackened the front 
of it. . . . The caterpillars would get into the house in spite of 
every precaution, and we would even find them upon the clothing 
hanging in the closets. We destroyed a great many caterpillars 
by burning, but their numbers did not seem to be lessened in the 
least. Other neighbors did not fight the caterpillars as we did, 
and so our efforts were in a measure rendered abortive. I think 
perhaps that if an organized effort had been made at that time to 
destroy the caterpillars they might have been stamped out. We 
lived on Myrtle Street for four years, and every year had the same 
plague. 

It should be noted that the Flinn family moved from 
Myrtle Street in 1886, having suffered from the pest from 
1882 until that time, which was three years before it became 
generally prevalent. Although the moths were so numerous 
near the Trouvelot house from 1880 to 1885, they did not 
become a serious pest farther down the street until about 
1886. We quote Mrs. M. F. Fenton : — 

In 1886 we lived at No. 10 Myrtle Street, and that summer we 
could not take any enjoyment out of doors. The caterpillars were 
very thick. We destroyed very many of them, but it seemed 
impossible to diminish their numbers. They seemed to be mul- 
tiplying steadily. A mere shake of a tree would bring them down 
on one in showers. They strip trees very quickly. 

Mr. D. W. Daly, No. 5 Myrtle Street, makes the follow- 
ing statement : — 

I moved here in 1884, and the next year got quite a crop of 
apples. I have three apple trees and a crab apple. In 1886 the 
gypsy-moth caterpillars appeared for the first time in any consider- 
able numbers in my yard. Nobody knew what they were. There 
were more of them farther down the street. In 1887 they came in 
droves, and before June 17 they had my trees stripped as clean as 
in December. After stripping the apple trees, they stripped a 
Sheldon pear tree as clean as the others. From 1887 to 1890, 
inclusive, I got no fruit. The caterpillars worked some little havoc 
on the lilacs. I was more fortunate than some others, whose trees 
were killed. I spent much time in killing caterpillars. I used to 



10 THE GYPSY MOTH. 

sweep them off the side of the house and get dustpanfuls of them. 
At night time we could hear the caterpillars eating in the trees and 
their excrement dropping to the ground. In the morning the walk 
would be covered with the latter. I inked my trees in 1888 and 
kept them out of the trees to some extent, but not wholly, for 
some of them blew into the trees, and they also got into them from 
the house. In 1887 I used to sweep them off in solid masses from 
the tree trunks. They used to get on the washing and stain it. 
Two of my apple trees since that time have never been the same 
as regards fruit-bearing qualities. I do not think I saw six cater- 
pillars all last summer. 

The Outbreak of 1889. 

During the years from 1869 to 1889, while the original 
colony of the moths was increasing and extending its terri- 
tory at Glenwood, stragglers therefrom were constantly 
scattering abroad to form new colonies. Later these joined 
with the parent swarm in forming the multitude which spread 
over the town. No particular attention was paid, during 
these years, to the moths which appeared here and there, for 
it must be borne in mind that the identity of the insect had 
been lost, and it was not generally known that there was a 
new insect in the land. The introduction of dispar by 
Trouvelot was forgotten or unknown, and wherever shade 
or fruit trees were defoliated, the damage was placed to the 
account of such old and well-known pests as the canker-worm 
or the tent caterpillar. 

Gen. S. C. Lawrence, the first mayor of Medford, who 
lives on Rural Avenue, a mile and a half to the west of 
Myrtle Street, testifying in 1893 at the hearing before the 
legislative committee on Finance, said : — 

I helped fight it [the moth] for years before the appointment of 
the commission, not knowing really what it was. 

Mr. John Stetson, living a mile to the west of Myrtle 
Street, who in 1889 sent specimens of the insect to the Hatch 
Experiment Station at Amherst for identification, said : — 

I discovered them in 1888 on a quince bush. I noticed one day 
that the leaves were all off from this bush. I examined it, and 
found there were worms there clustered on the limbs. 



ITS OUTBREAK IN 1889. 11 

At last a season arrived, that of 1889, when the moths 
became so abundant in Glenwood and in some other parts of 
Medford, and the consequent destruction of foliage so com- 
plete, that the food supply gave out. Armies of " worms" 
suddenly appeared in localities where they had never before 
been noticed, and seemed about to destroy every green thing. 
The growing caterpillars which had devoured the foliage in the 
wooded land around Glenwood, being checked on the south 
by the salt marsh, moved east, west and north. They re- 
inforced those in the yards and orchards along Myrtle Street, 
where most of the foliage had already been destroyed. The 
supply of food there being at once exhausted, the caterpillars 
marched from yard to yard and from tree to tree, their num- 
bers constantly augmented by those they met, which in quick 
succession were also forced by lack of food to join the hurry- 
ing host. Their enforced movements from tree to tree, from 
yard to yard, and from one street to another, in search of 
food, in the summer of 1889, are well described by the in- 
habitants. It will be seen that there was no general migra- 
tion in any one direction. The movements were local, and 
were directed mostly from those points where the foliage had 
been entirely destroyed toward others where some still re- 
mained. Such migrations had before been noticed in Glen- 
wood whenever the foliage had been nearly all devoured. 
Said Mrs. Belcher : — 

My sister cried out one day, " They [the caterpillars] are march- 
ing up the street." I went to the front door, and sure enough, the 
street was black with them, coming across from my neighbor's, Mrs. 
Clifford's, and heading straight for our yard. They had stripped 
her trees, but our trees at that time were only partially eaten. 

Mrs. R. Tuttle, 22 Myrtle Street, writes : — 

As fast as we gathered them, others would take their places. 
They seemed to come just like a flock of sheep. 

Mrs. I. W. Hamlin, corner Myrtle and Spring streets, 
said : — 

Our yard was overrun with caterpillars. . . . When they got 
their growth these caterpillars were bigger than your little finger, 



12 THE GYPSY MOTH. 

and would crawl very fast. It seemed as if they could go from 
here to Park Street in half an hour. 

Park Street, by reason of its nearness to Glenwood, soon 
became infested by the moth. Mr. F. M. Goodwin, living 
at the corner of Park and Washington streets, testifies inter- 
estingly to this : — 

Some years ago I saw the eggs of the gypsy moth plastered 
thickly on the bark of a willow tree on Spring Street. A great 
many millers were laying their eggs there. The moths later worked 
towards Park Street, and my neighbor's apple trees across the street 
were stripped clean, leaving the young apples hanging on the bare 
limbs. They crossed from this yard to mine, and I killed pecks 
of them. . . . The caterpillars came into my yard by night. I 
killed what I could during the day, and the next morning I would 
find them as thick as ever. 

While the moths were thus travelling to the west from 
Glenwood towards Medford Square, others were moving in 
all directions from places where they had become established 
in former years. They appeared in great numbers on Cross 
Street, at the residence of Mr. F. T. Spinney, Medford's 
postmaster, and crossed to the east side of the street. Their 
movements there are recorded in the words of people whose 
trees and gardens suffered. Said Mrs. Spinney : — 

I lived on Cross Street in 1889. In June of that year I was out 
of town for three days. When I went away the trees in our yard 
were in splendid condition, and there was not a sign of insect 
devastation upon them. When I returned there was scarcely a 
leaf upon the trees. The gypsy-moth caterpillars were over 
everything. 

Three other residents of this neighborhood speak as fol- 
lows : — 

In 1889 the caterpillars of the gypsy moth appeared at Spinney's 
place on Cross Street, and after stripping the trees there started 
across the street. It was about five o'clock one evening that they 
started across in a great flock, and they left a plain path across 
the road. They struck into the first apple tree in our yard, and 
the next morning I took four quarts of caterpillars off of one limb. 
(D. M. Richardson, then living at 8£ Cross Street.) 




PLATE IV. View of Salem Street, near corner of Fulton Street, Medford, 
showing elm trees which were defoliated in 1889 by the gypsy- 
moth. From a photograph taken in October, 1895. 



LOCAL OUTBREAKS. 13 

The caterpillars would travel on the fences in droves, and we 
could not go out of doors without getting them all over us. . . . 
When the caterpillars had cleaned out Mrs. Spinney's trees, they 
started across the street in droves for the orchards on the other 
side, and the next morning you could see the path which they had 
made across the street. (Mrs. W. H. Snowdon, 7 Cross Street.) 

At this time (summer of 1889) they were crossing from Mr. 
Spinney's by multitudes into yards on the other side of the street. 
It seemed but a few hours after they left Mr. Spinney's before 
they were all through my trees. They came literally in droves, 
and seemed to have a method in their movements. (J. C. Miller, 
3 Lauriat Place.) 

Another outbreak occurred on Vine Street, one-half mile 
from the Trouvelot house. This colony extended north 
across Salem Street to Fulton Street. Miss Helen T. Wild, 
G3 Salem Street, writes : — 

In 1889 the apple-trees in our neighborhood were attacked and 
stripped by the gypsy-moth caterpillars. They fed on the apple 
trees until there was nothing more to eat, and then started for the 
elms on the street. In the morning following the night when they 
finished the apple trees they were to be seen crossing the fence in 
swarms in the direction of the large street elms. They were crawl- 
ing fast, and were plainly heading for the elms. 

Mrs. George Fifield of Fulton Street, Medford, first 
noticed the caterpillars at the corner of Fulton and Salem 
streets. They were then travelling in lines along the side- 
walk. Several of these lines converged upon a large elm at 
the corner of the street, and a constant stream of larvae was 
ascending the trunk. A day or two later all the trees in the 
neighborhood were stripped, and in going toward Glenwood 
she found the same condition everywhere. 

Mr. J. O. Goodwin, writing in the Medford "Mercury" 
in 1890, describes the movements of the caterpillars in his 
neighborhood on South Street : — 

After devastating my neighbor's trees, they marched in myriads 
for my premises, fairly covering the fences, houses, out-buildings, 
grass land, currant bushes and concrete driveways with their troop- 
ing battalions. . . . The number of worms cultivated on the three 



14 THE GYPSY MOTH. 

or foui* worthless trees on the premises adjacent to my own is 
astonishing ; numbers fail to convey an adequate idea. The earth 
seemed to be covered with them. 

In June, 1889, there were similar local outbreaks over a 
tract extending as far as West Medford, two miles to the 
westward, and to Edge worth in Maiden, a mile to the east. 

The Swarming Caterpillars become a Serious Nuisance. 
The number of caterpillars that swarmed over certain 
sections of the town during the latter part of June and most 
of July, 1889, is almost beyond belief. Prominent citizens 
have testified that the ' ' worms " were so numerous that one 
could slide on the crushed bodies on the sidewalks ; and that 
they crowded each other off the trees and gathered in masses 
on the ground, fences and houses, entering windows, destroy- 
ing flowering plants in the houses, and even appearing in the 
chambers at night. The huge, hairy, full-grown caterpillars 
were constantly dropping upon people on the sidewalks 
beneath the trees, while the smaller larva? , hanging by in- 
visible threads, were swept into the eyes and upon the faces 
and necks of passers. The myriads that were crushed under 
foot on the sidewalks of the village gave the streets a filthy 
and unclean appearance. Ladies passing along certain streets 
could hardly avoid having their clothing soiled, and were 
obliged to shake the caterpillars from their skirts. Clothes 
hanging upon the line were stained by the larva? which 
dropped or blew upon them from trees or buildings. In 
the warm, still summer nights a sickening odor arose from 
the masses of caterpillars and pupa? in the woods and orchards, 
and a constant shower of excrement fell from the trees. The 
presence of this horde of gypsy-moth larva? had become a 
serious nuisance, and was fast assuming the aspect of a plague. 
The condition of affairs at this time is best shown by the 
following extracts from statements of residents : — 

The caterpillars were worst in 1887, 1888 and 1889. In the sum- 
mer of those years a good portion of my time was occupied in fight- 
ing the pest. The two large elms in front of our house were full 
of caterpillars, and had not a perfect leaf. In the night-time the 
noise of the worms eating in the trees sounded like two sticks 



THE CATERPILLAR PLAGUE. 15 

grating against each other. In the months of July and August I 
have gone out in the morning and raked up from under the elms 
a pile of leaves three or four feet high. These leaves had been 
cut off by the caterpillars, and usually there was a worm on the 
under-side of every leaf. I would pour kerosene over the mass 
and set it on fire, and the squirming of the caterpillars would 
cause it to rise up as if it had life of its own. The caterpillars 
used to cover the basement and clapboards of the house as high as 
the window sill. They lay in a solid black mass. I would scrape 
them off into an old dish-pan holding about ten quarts. When it 
was two-thirds full I poured kerosene over the mass of worms and 
set them on fire. I used to do this a number of times a day. It 
was sickening work. I have used in burning caterpillars five gal- 
lons of kerosene in three days. I have seen my fence black with 
the small caterpillars when they first hatched out in the spring. I 
used to kill them on the fence by pouring scalding water on them. 
The caterpillars used to be very thick in the grass, and there 
would be one under every fallen leaf. On certain occasions 
callers have had to wait at the front door until I could sweep the 
caterpillars off the steps so that they could come in without get- 
ting the worms on their clothing. (Mrs. Thomas F. Mayo, 25 
Myrtle Street.) 

On the morning of the fourth of July, 1889, my domestic and 
myself went around the whole of our fence and gathered ten or 
twelve quarts of caterpillars. A little while afterwai'ds they ap- 
peared to be just as thick as ever on the fence. On another occa- 
sion we gathered two quarts of eggs and caterpillars from the 
fence on one side of the yard only. ... It is not easy to give 
outsiders an idea of how bad the caterpillars were. If the State 
had not done something, I honestly think we should have had to 
move away from here. For several summers the women folks on 
our street made a regular business of killing caterpillars. We got 
fairly worn out catching them. I have seen Mrs. Mayo, across 
the way, sweep the caterpillars up in the gutter in great piles and 
burn them. . . . Another of our neighbors had the whole front of 
her house practically covered with caterpillars. One could hardly 
go out-doors without getting caterpillars on the clothing. You 
could see them travelling about. When they were thickest we did 
not pretend to go out the front door at all. We had the front 
doorsteps torn up, and found underneath a good many nests. 
There were thousands of eggs and caterpillars under the underpin- 
ning of the houses. In 1889 they got into our cellar, and we had 
it whitewashed. When the caterpillars were very small they would 
get all over the washing when it was hung out. There were no 



16 THE GYPSY MOTH. 

trees very near, but they would spin down from somewhere. (Mrs. 
R. Tuttle.) 

In the summer of 1889, while living on Park Street, Medford, 
we were literally overrun with the gypsy moth caterpillars. That 
summer we could have got the caterpillars out of the holes in the 
trees by pecks. After the caterpillars ate all the leaves off the 
trees, they went down into the grass, where they swarmed. When 
the plague was the worst that summer, I do not exaggerate when 
I say that there was not a place on the outside of the house where 
you could put your hand without touching caterpillars. They 
crawled all over the roof and upon the fence and the plank 
walks. We crushed them under foot on the walks. We went 
as little as possible out of the side door which was on the side 
of the house next to the apple trees, because the caterpillars 
clustered so thickly on that side of the house. The front door 
was not quite so bad. We always tapped the screen doors when 
we opened them, and the monstrous great creatures would fall 
down, but in a minute or two would crawl up the side of the 
house again. When the caterpillars were the thickest on the trees, 
we could plainly hear the noise of their nibbling at night when all 
was still. It sounded like the pattering of very fine rain-drops. 
If we walked under the trees we got nothing less than a shower 
bath of caterpillars. We had a hammock hung between the trees 
that summer, but we could not use it at all. The caterpillars 
spun down from the trees by hundreds, even when they were of 
a large size. We had tarred paper around the trees, but they 
crawled up the trunks in masses and went right over the paper. 
The bodies of those that got stuck in the printers' ink served as a 
bridge for their brethren. The caterpillars were so thick on the 
trees that they were stuck together like cold macaroni. A little 
later in the season we saw literally thousands of moths fluttering 
in the back yard. In the fall the nests were stuck all over the 
street trees. (J. P. Dill, then living on Park Street.) 

No one who did not see the caterpillars at that time can form 
any idea of what a pest they were. They got into the strawberry 
bed (although they did not eat the leaves), and I used to go out 
with a dustpan and brush and sweep them up by the panful. It 
seemed to us absolutely necessary to go out daily and make an 
effort to at least lessen their numbers. We killed many with boil- 
ing hot water, and would then dig a hole and bury them, so as to 
prevent a stench. Mr. Belcher was poisoned by them. While 
killing them upon the trees they would get upon his neck and blis- 
ter and poison it. It was impossible to stay long in the garden, 
for they would crawl all over one. We fought them for two or 



THE CATERPILLAR PLAGUE. 17 

three years before the commission took hold. "When they hatched 
out in the spring our fence would be one living mass. My sister 
and myself blistered the paint all off the fence with the scalding 
water that we poured on. When they were small it was almost 
impossible to keep them off one's person. It is a fact that we have 
scraped a quart of eggs at a time off the trees. We did the best 
we could to keep them down, but we could not get them all, for 
many would hide away and lay their eggs. (Mrs. William Belcher.) 

In 1889 the walks, trees and fences in my yard and the sides of 
the house were covered with caterpillars. I used to sweep them 
off with a broom and burn them with kerosene, and in half an hour 
they would be just as bad as ever. There were literally pecks of 
them. There was not a leaf on my trees. Back of the house and 
across the railroad track was a large tract of young-growth oaks 
and maples. They were all stripped. The caterpillars did not 
leave a leaf. The trunks and branches were covered with their 
cocoons. The cocoons hung in bunches as big as a pint dipper. 
The stench in this place was very bad. (Mrs. S. J. Follansbee, 
35 Myrtle Street.) 

When the caterpillars were small they would spin down on their 
threads and blow out into the street or even entirely across it. 
The caterpillars were a dirty pest. You could hardly go out of 
doors or sit down anywhere without getting them over you. Trees 
were either completely stripped so that not a green thing was to 
be seen on them, or else were eaten so that the skeletons of the 
leaves only remained. The caterpillars were very numerous on a 
large tree behind my house. I have scraped them off by the quart 
on the fence and shed adjoining the tree. They clustered as 
thickly as bees swarm. Before caterpillar time we used to see 
bodies of trees plastered all over with their egg clusters. They 
were so thick on certain trees that they reminded me of shells at 
the sea-shore. (J. H. Rogers, 17 Spring Street.) 

I lived on Spring Street when the caterpillars were thickest 
there. The place simply teemed with them, and I used to fairly 
dread going down the street to the station. It was like running 
a gantlet. I used to turn up my coat collar and run down the 
middle of the street. One morning, in particular, I remember that 
I was completely covered with caterpillars inside my coat as well 
as out. The street trees were completely stripped down to the 
bark. . . . The worst place on Spring Street was at the houses of 
Messrs. Plunket and Harmon. The fronts of these houses were 
black with caterpillars, and the sidewalks were a sickening sight, 
covered as they were with the crushed bodies of the pest. (Sylvester 
Lacy, 9 Daisy Street.) 



18 THE GYPSY MOTH. 

They [the caterpillars] were so numerous that when they clus- 
tered on the trunks they would lap over each other. A neighbor 
gathered in one day in my yard a peck of caterpillars, and poured 
kerosene over them and set the mass on fire, but many neverthe- 
less walked away from the burning mass. ... I used to scoop 
them off the sides of the house and the tree trunks with a dustpan. 
. . . Their eating in the trees sounded just like a breeze. Many 
got into the house, and we could not open the windows. I found 
them in the kitchen and in the bedrooms. I used to find them in 
the beds when I turned down the blankets. (Mrs. Spinney.) 

In the summer of 1889 the gypsy-moth caterpillars attracted uni- 
versal attention in Medford. They spread very fast over the town. 
I believe there were enough that summer to have caused the destruc- 
tion of all the green leaves in town by the following year, had 
their spread not been checked. During the summer the caterpillars 
were found in great numbers on South Street and in the eastern 
section of the town. Myrtle, Park and Pleasant streets and 
Magoun Avenue were overrun with the pests. Nobody knew what 
these caterpillars were until they had been identified in Amherst. 
They clustered on the bark of the South Street elms in multitudes. 
From the ground clear to the tops of the trees they lay thickly in 
the rough bark. (Ex-Selectman John Crowley.) 

The caterpillars were everywhere. They would get under the 
doorsteps and on the window-sills and even into the house. We 
found them under tables and even under the pillows. The windows 
could not be opened unless guarded by a screen. . . . When the 
caterpillars were full grown they would herd in great patches on 
the trunks. I have seen the end of Mrs. Spinney's house so black 
with caterpillars that you could hardly have told what color the 
paint was. In moth time I have seen the moths (it almost seemed 
by the bushel) crawling and fluttering around the bases of the 
trees. (Mrs. Snowdon.) 

In 1889 the trees on South Street were full of caterpillars. 
People did not know what they were at first. The four large 
street elms in front of my house were covered with them. . . . 
The sidewalk under one elm was covered with caterpillars which 
had dropped off. They were so thick on the tree that they had 
apparently crowded each other off. The front railing of Mr. 
Archibald's house on South Street looked as if it was covered with 
mud, the caterpillars were so thick on it. (F. E. Foster, 20 South 
Street.) 

I remember being at Judge Hayes's, South Street, one evening 
in the summer of 1889. Mrs. Hayes came in and said that she 
" never saw such a sight" in her life as the caterpillars presented. 



THE CATERPILLAR PLAGUE. 19 

We went out and found the fence rails literally covered with 
caterpillars. You could not set your foot down on the walks 
without crushing the worms. We took shingles and scraped 
quantities off the trunks of the big street elms. People used to 
scrape them off into piles and then burn them with kerosene. 
(Ex-Selectman W. C. Craig.) 

The caterpillars covered one side of my house so thickly that you 
could not have told what kind of paint was on it. It was impos- 
sible to keep them entirely out of the house. The women had to 
shake their clothing when they went into the house. People used 
to come from other parts of Medford to Myrtle Street just to see 
the ravages of the insect. (J. C. Clark, 11 Myrtle Street.) 

The caterpillars were so thick in the trees that you could hear 
them eating. They would get on the fences, until they made them 
fairly black. They would crawl upon and into the houses. They 
would get inside somehow, and it was a common thing to see them 
crawling on the table, aud we have even found them on the beds. 
They would get under steps, stones, and into old stove-pipes, old 
cans, boxes, in short, any place which, afforded a shelter. They 
crawled into the cellar windows. They were so thick on the street 
trees that people would walk out in the middle of the street, where 
there were fewer dropping down. It is no exaggeration to say 
that I have raked quarts of caterpillars off a tree. ... I have 
seen them crawling in great numbers on the rails of the Medford 
branch track. After a train had gone along, the rails would be all 
green with their crushed bodies. (William Taylor.) 

In the old days, when the caterpillars were so bad, the houses 
and fences were blackened with them. We used to sweep them off 
into a basin of kerosene. As you went up and down the street 
you would see no foliage except on pear trees. If you carried a 
sunshade down the street, the caterpillars would get all over it. 
(Miss R. A. McCarty, 26 Myrtle Street.) 

I recollect one elm tree in particular on Park Street which stood 
against the fence. There was an inked baud around the tree, and 
about two quarts of gypsy-moth caterpillars had collected below 
the band. Some of the caterpillars had got over the band, aud 
they had spun threads which served as ladders by which the others 
were crossing. (F. M. Goodwin.) 

We could not sit under the Porter apple tree, the caterpillars 
were so thick on it. They swarmed on the ground at the foot of 
the Baldwin. We poured boiling water on them. The fence was 
one mass of caterpillars, and they lay thickly under the clapboards 
and gutters. Our apple trees were stripped two years in succession. 
(Mrs. John Benson, 3 Cross Street.) 



20 THE GYPSY MOTH. 

About four to five p.m. they [the moths] flew about in thousands. 
Later in the season (1889) their eggs could be seen in clusters on 
the stone walls, fences, buildings and trees in great numbers, often 
nearly covering such objects. (James Bean, High Street.) 

Nothing too bad can be said of the caterpillars. If you sat down 
anywhere you would crush caterpillars. If the washing was hung 
out under trees infested with them, they would get on and stain 
the clean clothes. They were all over the sidewalks, and would 
drop down upon one from the trees. (Miss R. M. Angelbeek, 
24 Myrtle Street.) 

In 1888 and 1889 the gypsy-moth caterpillars were a terrible 
pest on Cotting Street and in that neighborhood. In a neighbor's 
yard [Mr. Rugg's] tbey brushed off of one apple tree at one time 
fourteen quarts of caterpillars. (Almon Black, 10 Cotting Street.) 

The elm trees in our yard were badly eaten by the gypsy-moth 
caterpillars. The ribs of the leaves alone were left. In the after- 
noon, when the sun got low, the caterpillars in the trees would get 
into the sun, and you could see the long line of them stretching 
away up the tree trunk. (Miss A.B.Bockman,21 Franklin Street.) 

The willows at the corner of Magoun Avenue were completely 
stripped for two years in succession. The moths were so thick at 
one time under the willows that I have collected them by the hand- 
ful and fed them to my hens. (Walter Sherman, 23 Spring Street.) 

In the evening we could hear the caterpillars eating in the trees. 
It sounded like the clipping of scissors. We kept the caterpillars 
down in our yard as much as possible, but it was discouraging to 
see them coming straight across the street in droves to our yard. 
They almost seemed to have a concerted plan of action. (Mrs. 
M. M. Ransom, 18 Lawrence Street.) 

The trees of our next-door neighbor, Mr. Randall, suffered very 
much. The caterpillars got into his evergreens, and were so thick 
that they made them look black. (Mrs. Hamlin.) 

In 1889 the brush lot at the corner of Lawrence and Spring 
streets swarmed with gypsy-moth caterpillars, and the young oaks 
were all stripped bare. Our house stood next to the brush lot. 
The caterpillars got upon the outside in great numbers, and we 
also found many inside. (J. G. Wheeler, Daisy Street.) 

The outside of my stable was literally black with caterpillars at 
the time when the gypsy moth was the thickest in this section. It 
was a disgusting sight. (R. Gibson, 5 Lawrence Street.) 

The year before the State began fighting the gypsy moth, I visited 
an acre of brush land in Glenwood, where the nests of the moth 
were laid by the hundred on stumps, bush stalks and other objects. 
This was in the fall of 1889. (J. Sherman, 76 Riverside Avenue.) 



THE CATERPILLAR PLAGUE. 21 

The caterpillars were thickest iu Glenwood, where in places they 
were like a carpet on the ground. Since the State took hold of 
the matter the trees have been in good condition, and excellent 
work has been done. (G. C. Russell, 11 Washington Street.) 

The caterpillars were a sickening sight when they were at their 
thickest. They used to make a living path, as it were, from the 
ground up into a tree. (Richard Pierce, foreman of the Sparrell 
estate, No. 90 Main Street.) 

We did what we could in our neighborhood to fight the cater- 
pillars, but they were so thick that one hated to go out of doors 
or on the street. We could plainly hear them at night eating in 
the trees. (Miss Helen T. Wild.) 

Many a time I have swept the caterpillars off by the dustpanful 
from the underpinnings of the house. (Mrs. E. M. Russell, then 
living on Cross Street.) 

In 1889 our apple, pear and crab-apple trees were all stripped 
by the gypsy-moth caterpillars. They either bore no fruit or else 
bore so late that the frost destroyed it. When the caterpillars 
were small we could see them in the daytime spinning down from 
the trees. At night you could not dodge them, and they would 
get into your neck and eyes. (F. H. Haushalter, 42 Myrtle 
Street.) 

A few years ago the caterpillars were terrible in Glenwood. 
You could not go down Myrtle Street without getting your shoul- 
ders covered. . . . We spent hours killing caterpillars, but there 
seemed to be two to every one we killed. (A. P. Perry, Myrtle 
Street.) 

I believe that, had the State taken no action in this matter, they 
would have increased to such an extent that they would have bred 
a pestilence in our country. They soon grew to the size of your 
finger, and the stench that arises from them when they are in large 
quantities is nauseating. (W. W. Fifield of Medford, before the 
legislative committee on Agriculture, Feb. 27, 1894.) 

Before public measures were taken in the matter, the foliage 
was completely stripped from all the trees in the eastern part of 
our town, presenting an awful picture of devastation, and pronhs- 
ing in a short time to kill every tree and shrub and all vegetation 
in any region visited by the creatures ; which shows how inade- 
quate individual effort was to cope with the subject. (J. O. Good- 
win, Medford.) 

People who wished to avoid the plague by removing to 
other towns or localities are said to have had some difficulty 
in disposing of their homes on account of the desolate appear- 



22 THE GYPSY MOTH. 

ance of the surroundings and the disgusting presence of the 
caterpillars. 

The bad condition of this section as regards the gypsy-moth 
plague was detrimental to real-estate valuations. (Mrs. Mayo.) 

The gypsy-moth plague hurt property in this section. Our 
house was advertised for sale, and when people came to look at 
the property they were apt to inquire why the leaves of the trees 
in the neighborhood were so badly eaten. When we told them it 
was the work of caterpillars, they would say that they would not 
live in such a locality. (Mrs. Flinn.) 

The condition of the Edgeworth district of Maiden in 
1889 was similar to that of Glenwood. Space permits but 
a few statements of residents : — 

The first year that the caterpillars were very bad was in 1889. 
They took the leaves off the trees so that they were as bare as in 
midwinter. We could not sit out on the lawn a minute, for the 
caterpillars would be all over one. My son used to climb a shade 
tree in front of the house and shake the caterpillars off. We 
would put a sheet underneath, and they would come down in 
showers. The top of the fence was covered so thickly with cater- 
pillars that you could not put a pin between them. The apple 
trees in the yard next to ours were stripped. The ribs of the 
leaves were left, and they looked ghastly. They leafed out again 
in June, but they bore no fruit. We used to gather the cater- 
pillars in a dustpan and put them in a pail. When the pail was 
full we would dump them out and burn them with kerosene. Our 
next-door neighbor, Mrs. Cahill, used to devote much time to 
killing the caterpillars. She would sweep them off the fence with 
a broom and burn them. We would see them in droves on the 
ground coming and going. (Mrs. John Dowd, 194 West Street.) 

In 1889 we were overrun with caterpillars. We did not know 
what to make of them. During that summer I could not use my 
front door, they were so thick around it. They were as thick as 
leaves. We had four apple trees, and they were stripped entirely 
bare. A second growth of leaves came out, but we got no fruit. 
For three years there was not an apple nor even a blossom on the 
trees. We could not have endured the plague, had the State not 
done something. (Mrs. Daniel Kelly, 209 West Street.) 

In 1889 the caterpillars were very bad. Every leaf was taken 
off my sycamore tree. I used to go out with a hoe and scrape the 
caterpillars off the trunk. If I sat out on my steps after dark 



ITS DESTKUCTIVENESS. 23 

I could hear them eating in the tree. My other trees were also 
badly eaten. (Mrs. Margaret Cronin, corner of Oakland and 
Sheridan streets.) 

The trees in the lower part of Edgeworth were badly eaten by 
the gypsy-moth caterpillars in 1889. They were thick on Oakland 
and Maiden streets and the Common. (T. J. Neville, Pearl 
Street.) 

In 1889 we had as many caterpillars as anybody. Yon could 
take a knife and scrape them off the trees. (Mrs. Margaret Con- 
nell, 97 Maiden Street.) 

The Destructiveness of the Moth. 
The caterpillars devoured the foliage of nearly all species 
of trees and plants in the worst infested region. During the 
years when the moth was most abundant, the destruction of 
or injury to fruit, shade and forest trees and fruit and garden 
crops was of course greatest. The destruction of trees was 
greatest in those localities where the moth had been longest 
abundant, for, though the smaller plants were often killed in 
one season as were also the less hardy trees, those trees 
which were lusty and vigorous would frequently withstand 
defoliation for two or three successive years before they finally 
gave up their hold on life. Thus the trees and gardens of 
residents of Glenwood suffered more in these respects than 
those of people in other parts of Medford. 

Trees Killed. 

In some cases where shade trees near dwellings were at- 
tacked they became such a nuisance as a harboring place for 
the caterpillars that they were cut down while still alive, as 
the only practical means of abating the nuisance. Fruit trees, 
however, were generally allowed to stand, and a fight was 
made to save them, which was in some cases successful, but 
in others all efforts to check the ravages of the moth and 
save the trees were futile. They finally died, were cut down 
and the stumps rooted up. 

The statements following are given in the words of people 
whose trees suffered : — 

We had three apple trees, four pear trees, one plum tree and one 
mountain ash killed by the gypsy-moth caterpillars. These trees 



24 THE GYPSY MOTH. 

were stripped of their foliage in the summer of 1887. They began 
to leaf out again late in the season, but were immediately stripped. 
The apple trees also put forth a few blossoms at this time. The 
following year they did not leaf out at all. They all died, and we 
cut them down. The apple trees were good-sized trees. One was 
a spice greening, another a Porter and a third an August sweeting. 
AYe also cut down a little locust tree which was badly eaten by 
the caterpillars, and the limbs of which died. The caterpillars 
swarmed in a tall Norway spruce in our back yard. They ate 
every bit of foliage on this tree, so that we had to cut all the limbs 
off. Nothing but the pole of this tree remains in our yard to-day. 
This tree was so full of caterpillars that when I shook a limb with 
a rake they would fall off in a shower and blacken the ground. 
There were so many of them that it sounded like pebbles falling. 
In addition to the trees, our currant bushes were stripped by the 
pest. (Mrs. Mayo, next-door neighbor of Trouvelot's.) 

The moths ruined me as regards fruit. They were worst in 
1889. Their ravages caused me to lose five nice apple trees, two 
cherry trees, one pear tree and five plum trees. ... I had a crab- 
apple tree that blossomed very full that spring, but the caterpillars 
covered it, and it died. One of the apple trees which the cater- 
pillars killed was a beautiful Ilubbardston. Some years I would 
get four barrels off of it to put away. All you will see of it to- 
day in my yard is the stump, over which we train nasturtiums. 
The spring following the ravages of the moth these trees leafed out 
a little, but not much, and finally died. (J. C. Clark.) 

In 1889 we lost three apple trees because of the caterpillars. 
They were stripped clean, and then leafed out and bloomed again 
in September. The next spring they leafed out a little, but did 
not bear, and finally died. (L. M. Clifford.) 

In another yard two large apple trees were stripped by the 
caterpillars, and died. The way this was brought about was as 
follows : the caterpillars stripped the trees early in the season, 
and, as they continued their ravages for nearly the whole summer, 
the trees had no chance to recover. The next year the trees 
would leaf out and be stripped again, and so on, until, unable 
longer to withstand such treatment, they died. (Almon Black.) 

Our next-door neighbor, Mrs. Kelly, had a fine Baldwin apple 
tree which the caterpillars stripped clean. They kept it stripped. 
One year it blossomed twice. It leafed out and blossomed and 
was stripped, and then leafed out and blossomed and was stripped 
again. Finally it would leaf out and blossom once, perhaps, and 
then it would leaf out but not blossom, and last year only one 
branch leafed out. The tree is nearly dead. This tree stood very 






,'.. '>$ 







PLATE V. Residence of J. O. Clark, No. 11 Myrtle Street, Medford. The 

picture shows a portion of the yard formerly occupied by 

fruit trees killed in 1889 by the gypsy moth. 



TREES KILLED AND CUT DOWN. 25 

near our window, and as we ate supper in the early evening we 
could distinctly hear the caterpillars chewing among the leaves. 
In the night-time I have frequently heard their " chip-chip- 
chipping " out in the shade trees on the street. In a yard adjoin- 
ing ours there is another apple tree which is more than half dead 
because of the ravages of the caterpillars. It used to bear 
splendid Baldwins, but last year there were not more than a dozen 
apples on the tree. The caterpillars used to strip it twice a year 
up to two years ago, when their numbers were greatly reduced. 
For two years in succession the caterpillars stripped two maple 
trees in front of our house. They ate all of the leaf except the 
ribs. We had two shade trees cut down which were in a dying 
condition because of the ravages of the caterpillars. This was 
some five or six years ago. On Otis Street also we had two trees 
which we cut down because the caterpillars ate them so badly. 
In Mrs. Kelly's yard there was a large balm of Gilead tree which 
was cut down because it was nothing more or less than a breeding 
place for the gypsy moth. The tree was a sight. The trunk and 
limbs were black with caterpillars. The tree stood close by Mrs. 
Kelly's house, and you can still see the discoloration under the 
eaves where the caterpillars clustered so thickly. Mrs. Meach, 
across the way, had a weeping willow cut down. (Mrs. Tuttle.) 

One of our sweet-apple trees died from the effects of the strip- 
ping by the caterpillars. The branches died one by one, but we 
let it stand one year, hoping that it would revive, but it did not. 
Our four Baldwin apple trees bore good crops until the caterpillars 
attacked them. By June you would not see a leaf on them, and 
they would remain in that leafless condition all summer. In the 
fall of 1892 we got our first crop of apples in seven years. (Miss 
E. A. McCarty.) 

A young maple which had been set out on the street in front of 
our house was stripped by the caterpillars and died. ... A young 
peach tree died, apparently because it was stripped by the cater- 
pillars. (Mrs. Flinn.) 

Two oaks on the street in front of our house were entirely 
stripped. The next year they did not leaf out, and were cut 
down. (J. W. Harlow, 58 Spring Street.) 

We cut down two cherry trees in our own yard because there 
were so many eggs, cocoons, etc., in the seams and holes. (Mrs. 
Snowdon.) 

I cut down three tall poplars in front of No. 19, where I now 
live, because they were so badly infested. I also cut down an 
apple tree because it attracted so many caterpillars and was so 
badly eaten. (William Taylor.) 



26 THE GYPSY MOTH. 

I had several balm of Gilead trees cut down because they were 
so badly eaten by the caterpillars. (Walter Sherman.) 

Our four apple trees which we cut down because of the pest 
yielded the year before eleven or twelve barrels of fine Baldwin 
apples. (J. P. Dill.) 

An apple tree was stripped twice, and we had no fruit. The 
caterpillars so nearly killed the tree that it has since that time 
borne very little. (Miss C. E. Camp, 28 Myrtle Street.) 

Fruit, Garden Crops and Flowering Plants Destroyed. 

The caterpillars destroyed not only the foliage of trees, 
but also fruit and vegetables. The long period of feeding 
made it possible for the larvas to secure a great variety of 
food. AYhen the supply of leaves in the trees fell short (and 
oftentimes before) they attacked the gardens. Little was 
spared but the horse-chestnut trees and the grass in the fields, 
though even these were eaten to some extent. There was 
evidently some choice exhibited ; for instance, pear trees 
were not so badly injured as the apple, but eventually most 
forms of vegetable life in the caterpillars' path were either 
injured or entirely destroyed. 

When fruit trees were stripped of their leaves, the imma- 
ture fruit either failed to develop or dropped from the tree. 
In some cases the fruit itself was partially eaten by the vora- 
cious caterpillars. The destruction of berries was often as 
complete. Many vegetables were ruined. Flower gardens 
were destroyed, and even greenhouses were invaded and rose 
bushes and other flowering plants eaten. Our space per- 
mits but a portion of the evidence of such devastations in 
Medford : — 

They [the caterpillars] ate nearly everything green in the yard, 
killing my rose bushes and doing much damage to the vegetables. 
(Mrs. Belcher.) 

I had quite a little vegetable garden, which was nearly ruined by 
the caterpillars. They destroyed the cucumbers and ate the tops 
of the tomatoes. They also destroyed some flowering plants. 
(Wm, B. Harmon, 5 Spring Street.) 

They [the caterpillars] even nibbled the young green pears, and 
I lost a good many in that way. My large cherry tree, which usu- 
ally bears two bushels, was stripped clean for two years running, 
and I got no fruit. The caterpillars ate all the young tomato vines 



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2"d 




GARDEN CROPS DESTROYED. 27 

and injured my rose bushes. . . . For three years previous to 1891 
my Baldwin apple tree bore no fruit on account of the ravages of 
the moth. It was stripped every year. (Mrs. Follansbee.) 

At my place on Woburn Street I had a small bed of spinach 
and dandelions which the caterpillars completely destroyed. My 
tomatoes suffered a like fate. (Ex-Selectman Craig.) 

In 1889 I had twenty-seven hundred young carnation pinks set 
out of doors, and the biggest part of them were destroyed by the 
caterpillars. This was in June. They were eaten off close to the 
ground. In 1890 the gypsy moth appeared in my greenhouses, 
and the foliage of the bushes in one rose house was completely 
eaten up. (A. "W. Crockford, 81 Spring Street.) 

It was almost impossible to have plants or green things of any 
sort. The caterpillars would eat anything that they could get hold 
of. The rose bushes were stripped. My mother plants yearly 
beans, peas, etc., but that year we did not get much from them. 
The parsley also was almost all eaten. (Miss R. M. Angelbeek.) 

The rose bushes were completely stripped, all the leaves and 
blossoms being lost. Despite the utmost efforts of two of us, it 
was impossible to keep the rose bushes free of caterpillars. They 
were very fond of the deutzias in the garden, and completely 
ruined them. (Mrs. Ransom.) 

They seemed particularly destructive to the Porter apple tree. 
The apples very largely fell off, and the inside of those that re- 
mained on the tree was not fit to eat. . . . The caterpillars ate 
the leaves of a white rose bush and a syringa in our yard, and the 
latter died from the effects of the stripping. (Mrs. Benson.) 

Our vegetable garden was practically ruined by them, peas, 
beans, corn, etc., being eaten. The garden of our next-door 
neighbor, Mr. Camp, suffered a like fate. . . . Our raspberry 
bushes were also stripped of their leaves. We lived later on 
Lawrence Street, and here also the caterpillars were trouble- 
some. An umbrella bush in the yard was killed by them. (Mrs. 
Flinn.) 

My usual apple crop was from fifty to one hundred barrels 
yearly ; but the second year of the caterpillar plague I did not 
get more than forty barrels. The third year I do not think I got 
more than thirty barrels. (D. M. Richardson.) 

After they had eaten the foliage of trees, the caterpillars would 
devour almost any green thing. (J. N. French, 7 Lawrence 
Street.) 

They were the most ravenous worms I ever saw. They would 
eat almost everything, taking the apples and the elms first. 
(John Cotton, 16 Cotting Street.) 



28 THE GYPSY MOTH. 

The caterpillars ate almost everything, feeding on small fruits 
and shrubbery as well as the trees. (Almon Black.) 

Our blackberry and raspberry bushes were badly eaten, and we 
got but little fruit from them that summer [1890]. (J. W. 
Harlow.) 

After eating the foliage of the trees, the caterpillars would at- 
tack the vegetables. (J. G. Wheeler.) 

The caterpillars even ate the grape-vine to some extent. 
(William Taylor.) 

How the People fought the Moth. 

No doubt the citizens of Medford did all that the people 
of any community would have done individually in righting 
the pest. Many of them owned their homes, and gave much 
attention to the care of their grounds. Each householder 
had a small lot of land, and most of them had gardens or 
small orchards to protect from insect ravages. There were 
many people in a given area each of whom had an interest 
in protecting his own small portion of that area. Many of 
these people spent most of their leisure time during the sum- 
mer months in fighting the caterpillars, killing great numbers 
of them. The number thus killed on Myrtle, Spring, Wash- 
ington, Park and Cross streets during a summer must have 
checked considerably the increase of the moth. Many peo- 
ple banded the trunks of their trees with tarred paper, to 
which they applied tree ink as a protection against the mi- 
grating worms. This was a partial success, if the bands 
were carefully watched and the caterpillars which gathered 
below them killed in time to prevent their crossing the bands 
by mere force of numbers. A considerable part of the fruit 
crop was saved in some orchards in this way, the tree ink 
having the effect of turning many caterpillars away from 
banded trees to those left unhanded. Yet, in spite of all 
checks, the moths on Myrtle Street increased and spread so 
as in time to overwhelm the town. It is known that people 
there fought them with fire, water and coal oil from five to 
eight years before they became prevalent in other parts of 
Medford. 

Extracts from statements graphically describing the meth- 
ods used are given herewith : — 



FOUGHT BY THE PEOPLE. 29 

Many citizens scraped off all the caterpillars that they could, 
and killed them. The caterpillars were scraped off in masses as 
high up as a man could reach. Some people burned them off by 
means of a rag soaked in kerosene and tied to a pole. (Ex- 
Selectman Crowley.) 

At the time when the gypsy-moth caterpillars were thickest in 
this neighborhood I used to spend all my leisure time fighting 
them, and then failed to keep them down. . . . We used to take 
a can with a little kerosene in the bottom and pick the caterpillars 
off into it and later bury them in the ground. In a half -hour I 
have picked a canful off one apple tree. (Mrs. Ransom.) 

The caterpillars were of an enormous size, and would lie in clus- 
ters on the tree trunks. We used to scrape them off into a pail. 
(Mrs. Charles A. Lawrence, then living at 10 Cotting Street.) 

We used to destroy the caterpillars on the fences by pouring 
scalding water on them. We burned with kerosene those in the 
trees. We would go out several times a day and kill them. We 
also used to scrape them off into cans. (Mrs. A. H. Plummer, 
14 Lawrence Street.) 

We spent hours killing caterpillars on them [street elms]. We 
would get two quarts off at a time. They were very large. They 
got into every crevice and under every piece of bark. Our neigh- 
bor across the way, Mrs. Turner, used to go out with a pail of hot 
water and poke the caterpillars into it with a stick. My son used 
to tie a rag soaked in kerosene around a pole and set it on fire and 
singe them off the trunks of the trees. (F. E. Foster.) 

I put a piece of stout paper about a foot wide around the tree at 
my place for the gypsy-moth larvae to go under. I visited it a 
number of days later and found the trunk of the tree under the 
paper to be entirely covered with the insects. There were hun- 
dreds of them. A neighbor, Mr. Dutton, tried a similar experi- 
ment with a strip of carpet, Avith like results. (James Bean.) 

We used to take lighted candles and run them along under the 
fence rails and scorch the eggs there. (Miss R. M. Angelbeek.) 

I had charge of this estate [Sparrell estate, Main Street], and I 
killed a great many caterpillars by brushing them off the trees with 
a broom and crushing them. After brushing them off the trees, I 
would wait half an hour and then there would be just as many 
again on the trees. I could have gathered a half-bushel of cater- 
pillars every evening through their season. (Richard Pierce.) 

I used to burn them in the trees with torches. . . . We killed 
them on fences with boiling water. (Mrs. Spinney.) 

We used to sweep them off into a dustpan and burn them, but in 
a short time they would be as thick as ever on the tree again. . . . 



30 THE GYPSY MOTH. 

The next spring (1890) I found the apple trees in my own yard 
were pretty well infested with nests. I had my hired man scrape 
them all off with a putty knife. We collected them in a dish and 
burned them up in the furnace, where they snapped and crackled. 
(J. E. "Wellington, Wellington.) 

I fought the caterpillars in my own yard by placing cloths in 
the crotches and around the trunks of the trees. The caterpillars 
collected in great numbers under the cloths, and were then easily 
destroyed. (S. F. Weston, 11 Fountain Street.) 

We had both the steps and the fence split up and burned, so 
as to deprive the pest of its harboring places. I have frequently 
gathered half a coal-hodful of caterpillars from the fence within a 
short space of time. In twenty minutes they seemed to be just as 
thick as ever. We burned many pecks of them in all. (William 
B. Harmon.) 

In the evening, after the men had come home from work, you 
could see fires in all the yards, where they were burning cater- 
pillars. (Mrs. Fenton.) 

For four or five years I fought the gypsy-moth caterpillars, as 
did my neighbors, but could not keep them down. ... By put- 
ting tarred paper around the trees aud keeping the printers' ink 
fresh, I succeeded in a measure in keeping the caterpillars out of 
the trees. One tree which was very full of caterpillars I sprinkled 
with the garden hose and knocked the pests out of it. The tarred 
paper kept them from crawling up again, and they would collect 
in a mass below the band. (J. N. French.) 

When the caterpillars were very small the fences were black 
with them. We used to kill them on the fences by taking tea- 
kettles and walking along beside the rail and pouring boiling water 
on the vermin. . . . We would scrape them from the tree trunks 
with hoes and burn them with kerosene. We used to build little 
fires at the base of a tree and collect the eggs and burn them. 
(Mrs. Snowdon.) 

The greenhouse was full of them [caterpillars]. The warmth 
caused them to hatch out early. I destroyed most of them by 
picking off the leaves and burning them, and also by spraying 
with an emulsion of whale-oil soap, kerosene and ammonia. (A. 
W. Crockford.) 

For six weeks a great deal of our time was devoted to killino- 
these caterpillars. . . . We would go out in our yard time after 
time during the day and gather the caterpillars in dishes. Time 
and again I have stayed out in the yard for two hours at a time, 
catching caterpillars ; but in half an hour afterwards they seemed 
to be just as thick again. (Mrs. Hamlin.) 




PLATE VII. Cherry, red cedar and yellow pine trees attacked 

by the gypsy moth. From a photograph 

taken in Medford. 



INCREASING ON NEGLECTED ESTATES. 31 

During the summer of which I speak (1889) my currant bushes 
were also attacked. They were covered with caterpillars, but I 
saved them by sprinkling them twice a day with a solution of soap- 
suds and kerosene. (J. C. Clark.) 

The Moth multiplies on Neglected Lands. 
Though there were many people who did their utmost to 
destroy the moths, there were others who made little effort 
in that direction. There was waste land which no one cared 
for, and in such places the moth increased apace, until the 
advances of the ravenous larvna could no longer be stayed by 
individual effort : — 

I think, if every one had taken hold and fought the moths in the 
beginning, they might have been stamped out right in the place 
where they originated. The trouble was that some people would 
not do anything. Some people on the street were tenants only, 
and therefore took little or no interest in the condition of their 
yards. I remember the case of one house which was vacant dur- 
ing one summer. The caterpillars in that yard were a sight. 
Another neighbor, not owning his house, and not intending to 
stay there, was overrun in a like manner. (William Taylor.) 

Other residents make similar statements : — 

A house near by being unoccupied, the caterpillars in the gar- 
den there had full swing, there being no one to fight them. This 
yard was a recruiting place for the whole neighborhood. No 
sooner would we get our own yard comparatively free than a lot 
more would crawl around on the fence from the other yard. 
(Mrs. Plummer.) 

One difficulty in fighting the caterpillars used to be that now 
and then a neighbor would not do anything to keep them down on 
his own land. As a consequence, the caterpillars, after stripping 
this man's trees and getting about three-quarters grown, would 
migrate into the other yards and be even more destructive, their 
voracity increasing with their size. (J. N. French.) 

The only way I suffered was because my neighbors were negli- 
gent. The caterpillars blew over on to my trees. ... I saw them 
coming from my neighbor's premises on a concrete walk extending 
along where my fruit trees grow. The walk was literally covered 
with these worms when they were about the size of your little 
finger, so that it appeared like a carpet. (J. O. Goodwin, before 
the legislative committee on Agriculture, Feb. 27, 1894.) 



32 THE GYPSY MOTH. 

There were some people on Cross Street who used to do nothing 
in the way of fighting the caterpillars, and for that reason the work 
of individuals failed to cope with the pest. (Mrs. Spinney.) 

The Plague brought to the Attention of the Public 

at Large. 

Messrs. John Stetson, W. C. Craig, J. O. Goodwin and 
Dr. Pearl Martin, all of Mcdford, were among the first to 
call public attention to the ravages of the moth. Mr. Stetson 
first noticed the larva? of the moth in 1888 at his place on 
South Street, nearly a mile from the Trouvelot house. In 
June, 1889, when they began to defoliate the trees in his 
neighborhood, he took a specimen for identification to Hon. 
Wm. R. Sessions, secretary of the State Board of Agricult- 
ure. Mr. Sessions, being unable to identify it, advised 
sending specimens to the Hatch Experiment Station at 
Amherst. This was done, and the caterpillars were received 
at the station June 27. Professor Fernald, the entomologist 
of the station, was absent at that time in Europe, and no one 
at the station immediately recognized the species. After a 
thorough search through American entomological literature, 
the conclusion was reached that the insect was foreign. 
Recourse was then had to European works in the library of 
the entomologist, and after a slight search through the 
authorities, Mrs. Fernald and her son, Dr. H. T. Fernald, 
identified the caterpillars as those of Ocneria dispar, known 
in England as the "gypsy moth," in Germany as the 
" sponge spinner" or stem caterpillar, and in France as " le 
zigzag." Mr. Stetson was notified of the identification, and 
information regarding the outbreak was immediately sent to 
Professor Fernald. Later he observed in Germany the 
ravages of this insect, and consulted with European ento- 
mologists in regard to the matter. All these authorities 
regarded the gypsy moth as a serious pest, and the opinion 
was expressed that it would become far more destructive 
than the potato beetle, by reason of the number of its food 
plants.* 

In the mean time the people of Medford were becoming 
alarmed. 



* See Bulletin of tlie Hatch Experiment Station, November, 1889. 



IT IS FOUGHT BY THE TOWN. 33 

TheMedford "Mercury" of June 28, 1889, contains this 
item : — 

The army-worm has struck Gl on wood and Park Street gardens, 
stripping trees of their foliage. 

About this time Mr. Craig, then one of the selectmen of 
Medford, became interested in the outbreak. The condition 
of the trees and gardens so alarmed him that he immediately 
brought the matter to the attention of the town officials. He 
writes : — 

In 1889 I was connected with the town government of Medford. 
Coining out one day on the train from Boston, I noticed that the 
trees in Olenwood had the appearance of having boon burned. I 
made a remark to the effect that the trees had been burned, when 
a lady said, " That is the work of the army- worm." In company 
with Mr. J. O. Ooodwin I investigated the matter, and found that 
the insects wmich were preying on the trees were not army-worms. 
Being a selectman, I conferred with the other members of the 
Board, but we had nothing to do with the trees on the streets or 
in the orchards of the town. Mr. Ooodwin and myself waited on 
the road commissioners and asked them to expend some money in 
stopping the ravages of the pests, which were the gypsy-moth 
caterpillars. The commissioners at that time had no money wdiich 
they could expend for such a purpose, but were in full sympathy 
with the movement and did all they could to further it. I saw 
ex-Senator Boynton, General Lawrence, J. Henry Norcross and 
other leading citizens in regard to the matter, and it was agreed 
that some action must be taken. ... It was the sentiment that 
the road commissioners should do wdiat they could to stop the rav- 
ages of the caterpillars. 

The alarming condition of the shade trees was considered 
sufficient cause for immediate action. At a meeting of the 
road commissioners on July 1, it was decided (pending action 
by the town authorities) to put fresh ink on the bands of the 
trees on the streets where the caterpillars were most numer- 
ous. These trees, in common with other street trees in the 
town, had been banded earlier in the year as a guard against 
the ravages of the canker-worm. The inking of the tree 
bands was done the next day, and at night " it was found 



54 THE GYPSY MOTH. 

that thousands of the pests were bunched beneath the printers' 
ink" (Medford "Mercury," July 5). 

Though this protection of the trees had the effect of allevi- 
ating the injury to those protected, it hastened the diffusion 
of the caterpillars and drove them to other plants and to 
other localities where trees were not banded, thus extending 
the area of the injury until it included most of the trees in 
the eastern part of the town. There were some localities, 
however, that escaped the general devastation. At a town 
meeting held on July 15 it was voted, on petition of the 
road commissioners, to appropriate the sum of three hundred 
dollars for the care of shade trees. This appropriation of 
three hundred dollars was in addition to the usual appropri- 
ation of five hundred dollars for the care of shade trees made 
earlier in the year. It was expended under the direction of 
Dr. Pearl Martin, one of the road commissioners. A num- 
ber of men were employed in scraping off the egg clusters of 
the gypsy moth from shade trees, chiefly on Park and Salem 
streets, where the trees were badly infested. The eggs were 
burned with kerosene. In addition to the work done by the 
town, much effort and money were expended by citizens in 
the endeavor to free their premises of the moth. 

Professor Fernald, having meantime returned from Europe, 
visited Medford and viewed the infested district. Later, in 
company with Hon. Win. R. Sessions, secretary of the State 
Board of Agriculture, he visited and inspected Medford 
again. These two gentlemen waited on Chairman Wadleigh 
of the Board of Selectmen, and urged that the selectmen take 
action to petition the General Court for legislation authoriz- 
ing the State Board of Agriculture to exterminate the cater- 
pillars. This course was approved by the selectmen at their 
next meeting, October 25 ; but, as the Legislature was not then 
in session, no immediate action was taken. In November an 
illustrated bulletin on the gypsy moth was issued by Professor 
Fernald at the Hatch Experiment Station. By authority of 
the State Board of Agriculture and with the co-operation of 
the Massachusetts Society for Promoting Agriculture, an edi- 
tion of forty-five thousand copies was printed, and mailed 
to tax-payers in Medford and vicinity. The bulletin was 
printed in full in the Medford " Mercury" on December 6. 



PUBLIC INTEREST AROUSED. 35 

The task of destroying the eggs, which had been delegated 
to the Medford road commissioners, was far greater than had 
been anticipated, and the money appropriated was soon ex- 
pended, while only a small part of the eggs had been 
destroyed. While the work was in progress Dr. Martin saw 
that the moths were so numerous and so widely distributed 
that the town authorities could not cope with them. At a 
meeting of the selectmen, December 10, he appeared in 
behalf of the road commissioners and advised applying to 
the Legislature for State aid. The Board voted that the 
clerk should communicate with Secretary Sessions of the 
State Board of Agriculture ' ' in relation to measures to be 
taken to place this matter properly before the next Legis- 
lature." 

At the next meeting of the selectmen, December 17, a 
communication was received from the Hatch Experiment 
Station, advising that the Legislature be petitioned for an 
appropriation to exterminate the moth. The clerk, reporting 
in regard to his interview with Secretary Sessions, recom- 
mended that petitions in favor of such an appropriation be 
circulated in Medford and vicinity for presentation to the 
Legislature. Messrs. Wadleigh and Lawrence were appointed 
a committee to draw up such petitions. Mr. Lawrence was 
also appointed a committee to confer with Secretary Ses- 
sions in regard to preparing a bill to be presented to the 
Legislature. 

In December, Prof. H. H. Goodell, president of the 
Massachusetts Agricultural College, wrote to Governor-elect 
Brackett, urging that measures should be taken by the in- 
coming Legislature to provide for the extermination of the 
gypsy moth. 

In his message to the Legislature of 1830 Governor 
Brackett said : — 



A new enemy is at present threatening the agriculture, not only 
of our own State, but of the whole country. It is the gypsy moth, 
said to attack almost every variety of tree, as well as the farm and 
garden crops. The pest is spreading with great rapidity, and, if 
its eradication is to be attempted, immediate measures are of the 
utmost importance. 



36 THE GYPSY MOTH. 

A petition for legislation for the extermination of the 
gypsy moth was presented to the Legislature by the select- 
men of Medford, Jan. 15, 1890. Other towns joined in the 
movement. On January 21, the selectmen of Arlington pre- 
sented a petition. Soon after, petitions were presented by 
the boards of selectmen of Everett, Winchester, Stoneham 
and Wakefield, and by city officials of Maiden and Somer- 
ville. A petition was presented from the State Board of 
Agriculture, headed by President Goodell of the Agricultural 
College ; also one from the Essex County Agricultural So- 
ciety. The Massachusetts Horticultural Society took an 
active part in the movement, petitioning the Legislature as 
follows : — 

The Massachusetts Horticultural Society, recognizing the dan- 
gers threatening the agricultural interests of the State by the sud- 
den appearance in the town of Medford of a dangerous insect pest, 
petitions the Legislature, in support of the petition of the citizens 
of Medford and adjacent towns, for State aid in stamping it out. 

The joint standing committee on Agriculture of the Massa- 
chusetts Legislature visited Medford early in 1890, and saw 
the masses of egg clusters on the trees.* Public interest 
having in the mean time been aroused, an act appropriating 
twenty-five thousand dollars "for the extermination of the 
Ocneria dispar or gypsy moth" was passed. f This was ac- 
complished mainly through the influence and untiring efforts 
of Mr. J. Henry Norcross of Medford, then a member of the 
House of Representatives, aided by hearty co-operation of 
Representatives from the neighboring towns. The act was 
approved March 14, 1890, and is here given in full : — 

[Chapter 95.] 

An Act to provide, against depredations by the insect known 
AS THE ocneria dispar or gypsy moth. 

Be it enacted, etc., as follows : 

Section 1 . The governor by and with the consent of the coun- 
cil is hereby authorized to appoint a commission of not exceeding 
three suitable and discreet persons, whose duty it shall be to pro- 

* " The walls and almost every tree were almost wholly covered with nests." 
^Ex-Senator Low, before the legislative committee on Agriculture, Feb. 27, 1894.) 
f Dispar has now been referred to the genus Porthetria. 



PROVIDING AGAINST ITS DEPREDATIONS. 37 

vide and carry into execution all possible and reasonable measures 
to prevent the spreading and to secure the extermination of the 
ocneria dispar or gypsy moth in this Commonwealth ; and to this 
end said commission shall have full authority to provide itself with 
all necessary material and appliances and to employ such compe- 
tent persons as it shall deem needful ; and shall also have the right 
in the execution of the purposes of this act to enter upon the lands 
of any person. 

Sect. 2. The owner of any land so entered upon, who shall 
suffer damage by such entry and acts done thereon by said com- 
mission or under its direction, may recover the same of the city or 
town in which the lands so claimed to have been damaged are sit- 
uate, by action of contract; but any benefits received by such 
entry and the acts done on such lands in the execution of the pur- 
poses of this act shall be determined by the court or jury before 
whom such action is heard, and the amount thereof shall be applied in 
reduction of said damages ; and the Commonwealth shall refund to 
said city or town one-half of the amount of the damages recovered. 

Sect. 3. Said commission shall have full authority to make 
from time to time such rules and regulations in furtherance of the 
purposes of this act as it shall deem needful ; which rules and 
regulations shall be published in one or more newspapers published 
in the county of Suffolk, and copies of such rules and regulations 
shall be posted in at least three public places in each city or town 
in which said ocneria dispar or gypsy moth shall be found by such 
commission to exist, and a copy thereof shall be filed with the city 
or town clerk of each city or town. Any person who shall know- 
ingly violate any of the provisions thereof shall be punished for 
each violation by a fine not exceeding twenty-five dollars. 

Sect. 4. Said commission shall keep a record of its transac- 
tions and a full account of all its expenditures, in such form and 
manner as shall be prescribed by the governor and council, and 
shall also make return thereof to the governor and council at such 
time or times and in such form as shall be directed by the governor 
and council. The expenses incurred under this act shall be paid 
by the Commonwealth, except claims for damages by the entry 
upon the lands of any person and acts done thereon by said com- 
mission or by its direction, which shall be paid as provided in sec- 
tion two of this act. 

Sect. 5. The governor and council shall establish the rate of 
compensation of the commissioners appointed under this act, and 
the governor may terminate their commissions at his pleasure. 

Sect. 6. Any person who shall purposely resist or obstruct 
said commissioners or any person or persons under their emplov, 



38 THE GYPSY MOTH. 

while engaged in the execution of the purposes of this act, shall 
be punished by a fine not exceeding twenty-five dollars for each 
offence. 

Sect. 7. It shall be unlawful for any person to knowingly 
bring the insect known as the ocneria dispar or gypsy moth, or 
its nests or eggs, within this Commonwealth ; or for any person 
knowingly to transport said insect, or its nests or eggs, from any 
town or city to another town or city within this Commonwealth, 
except while engaged in and for the purposes of destroying them. 
Any person who shall offend against the provisions of this section 
of this act shall be punished by a fine not exceeding two hundred 
dollars or by imprisonment in the house of correction not exceed- 
ing sixty days, or by both said fine and imprisonment. 

Sect. 8. To carry out the provisions of this act a sum not ex- 
ceeding twenty-five thousand dollars may be expended. 

Sect. 9. This act shall take effect upon its passage. [Ap- 
proved March 14, 1890. 

The Commission of 1890. 

In accordance with the provisions of the act of March 14, 
Governor Brackett appointed a salaried commission, consist- 
ing of Warren W. Kawson of Arlington, then a prominent 
member of the State Board of Agriculture, Dr. Pearl 
Martin of Medford and J. Howard Bradley of Maiden. 

The commission organized in Medford, March 22, with the 
choice of Mr. Rawson as chairman and Mr. Bradley as 
secretary and general superintendent. The records show 
that in April, Mr. Samuel Henshaw of the Boston Society of 
Natural History was appointed entomologist to the com- 
mission. Headquarters were established in Medford, and 
meetings of the commission were held almost daily until the 
last of July and several times per month during the rest of 
the year. 

The commission began its labors by a partial inspection 
of the known infested district, for the purpose of discovering 
and marking the infested trees, shrubs and other objects. 
The infested trees were marked with a red tag. The moth 
was soon found in many localities outside the restricted dis- 
trict to which it was at first supposed to be confined. This 
district did not exceed one- half mile in width and one and 
one-half miles in length. The inspection of 1890 justified 



THE FIRST COMMISSION. 39 

the commissioners in the assumption that fifty square miles 
of territory were then more or less infested. 

It soon became apparent that the appropriation of twenty- 
five thousand dollars would be entirely insufficient for the 
needs of the season's work, chief of which was the expensive 
item of spraying. On May 9, in a communication addressed 
to Governor Brackett, the commission reported having found 
the infested territory " some sixteen times as large as first 
represented," and asked for an additional appropriation of 
twenty-five thousand dollars. This appropriation was made 
by the Legislature and approved June 3, 1890. The force 
of employees was increased as the season advanced, and 
reached its maximum strength in June, eighty-nine men 
being employed from June 16 to 28. 

During the month of April many eggs of the moth were 
scraped from the trees and destroyed by the employees of the 
commission. Early in May the spraying of infested trees 
and foliage with Paris green was begun and continued until 
about the middle of July. This was the principal work of 
the summer. Fifteen teams were in use, and spraying was 
done in Medford, Maiden, Arlington, Chelsea and Everett. 
The greatest amount of spraying was done in the Glenwood 
and Wellington sections of Medford and the Edgeworth dis- 
trict of Maiden. 

Another feature of the season's work was the guarding of 
highways leading out of Medford and Maiden, with the view 
to preventing the further dissemination of the moth by means 
of vehicles. About a dozen special policemen were em- 
ployed in this duty from early in June until the last of July. 
They were on duty twelve hours in the day. Caterpillars of 
the moth were found on many vehicles going out of the in- 
fested district. 

Large kerosene torches were used during the summer to 
burn the clustering caterpillars. Considerable cutting and 
burning of infested trees and bushes was also done, the chief 
work of this sort being in the badly infested woodland north 
and south of the railroad at Glenwood. About twenty acres 
of ground were thus cleared. 

In September and October a few men were engaged in 
scraping eggs from the trees in Medford, Maiden, Somerville, 



40 THE GYPSY MOTH. 

Arlington, Everett, Cambridge and Chelsea. In November 
the force was slightly increased, and an inspection was made 
of certain parts of the infested territory. The cavities of 
some trees along the highways were closed with cement. 
On December 6 all men in the employ of the commission 
were discharged, and the field work of 1890 closed. 

The Abundance and Deslructiveness of the Moth in 1890. 
Keferring to the work of 1890 and the numbers of the 
moth, Mr. E. J. Cadey, an ex-employee of the commission, 
said : — 

At the time when the commission first started I saw the eggs of 
the moth on trees in such numbers that the trees had a spongy 
appearance, and the men who gathered them used large-sized pails, 
holding about a peck. Some days we filled these pails twice and 
occasionally three times. Especially was this the case at the Wel- 
lington willows, in Glenwood, where the moths originated. The 
walls of an old shed were one yellow mass of eggs. Early in the 
summer, previous to the spraying season, on sixteen acres of 
woodland and brush on land of Mr. Pinkert near the Boston & 
Maine Railroad, there was not a green leaf to be seen. We after- 
wards cut these sixteen acres. There were five or six willows on 
the corner of Spring and Magoun streets that were so thickly 
covered with pupa? that the bark could not be seen. In 1890 I do 
not think there was a whole leaf in Medford, and the people com- 
plained of a very disagreeable stench. 

Mr. William Enwright, who was also employed by the 
commission in 1890, writes : — 

I was sent to Glenwood to the brick yards. Here I found the 
bricks completely covered with the caterpillars. Nearly opposite 
here, on Lawrence Street, there was an old barn literally covered 
inside and out with nests and caterpillars. Trees were com- 
pletely stripped. The streets and sidewalks were so covered that 
it was almost impossible to step without crushing some of the 
caterpillars. In the fall of the first year, when we were cleaning 
the nests from the rubbish, we used shovels to shovel them into 
cans. You could not walk in the woodland without being covered 
with caterpillars. In 1890 Mr. Bradley drove his horse through 
the woods, and the horse's mane and tail were covered with 
caterpillars. 



ITS RAVAGES IN 1890. 41 

Mr. G. T. Pierce, who was employed in 1890, writes : — 

"When I was working at Dr. Newton's place on Highland Ave- 
nue, Somerville, on seventeen or eighteen apple trees you could 
not find a leaf that had enough left of it to call it a leaf. Most 
of them were only a stub of the midrib. In a large bunch of 
willows at Wellington, which the old commission cut down almost 
the first thing they did, the trunks were literally covered with egg 
clusters from the ground up, so that I doubt if you could find 
many places where you could put your hand on the surface of the 
tree without covering one or more nests. 

Mr. C. S. Mixter, an ex-employee, testified as fol- 
lows : — 

In one place in Chelsea the nests were so thick in 1890 that you 
could not put your finger down without striking a nest. We 
scraped the nests off. We had several panfuls. 

Despite the great destruction of the moth by the commis- 
sion during the work of 1890, the ravages of the creature 
in Medford were still serious. Although the injury wrought 
was not as widespread as in 1889, the stripping of trees 
and the consequent loss of fruit crops still continued. On 
Spring Street, in 1890, the moths appear to have been at 
their worst. Mr. W. B. Harmon, of No. 55 Spring Street, 
says : — 

In the summer of 1890 the caterpillars destroyed all our fruit. 
They attacked and stripped the apple trees first, and then turned 
their attention to the pear trees, which they also stripped. The 
young fruit was entirely ruined, and we had nothing that fall. 
The trees in places were actually black with the caterpillars. 
They would collect in great bunches, and we would sweep them 
off with a broom. . . . We could not step out of doors, either 
upon the grass or the walk, without crushing the caterpillars 
under foot. Over our front door the house was black with them. 
We would clean them off every morning, but in an hour it would be 
black again. People could not come in that way. It is no exag- 
geration to say that there were pecks of the caterpillars under the 
doorsteps and on the fence. . . . The next lot to ours was a 
vacant brush lot. It actually swarmed with caterpillars, and they 
came from there into our yard by thousands. 



42 THE GYPSY MOTH. 

Other residents of the neighborhood give similar testi- 
mony : — 

In 1890 we lived on Spring Street, and that year the caterpillars 
seemed to be at their worst. You could not go along the street 
after dark without getting them all over you. (Mrs. Fenton.) 

Four years ago (1890) I saw the gypsy-moth caterpillars by the 
thousand on the Sherman lot on Spring Street. I never saw such 
a sight. Their eggs were as thick on the big willows as spawn in 
a fish. (A. W. Crockford.) 

In 1889 the washing on our clothes reel seemed to have a dingy 
appearance, and I found tiny black worms on the clothes. These 
would blow over from the Myrtle Street yard adjoining. They 
were young gypsy-moth caterpillars, although at that time I did 
not know what they were. The next year they appeared in our 
yard by swarms. The board walks were completely covered with 
them. It was impossible to walk without crushing them under 
foot. On going out of doors they would get on one's clothing. 
Our trees and other green things were stripped twice and leafed 
out twice. The foliage of everything that was set out in our yard 
was riddled; the woodbine alone escaped. We became dis- 
couraged, and let things go. The grape-vine suffered. One 
morning Mr. Merrill picked caterpillars for an hour and a half off 
one rose bush. The trunk of the umbrella tree in the yard was 
completely hidden by the mass of caterpillars stuck together. I 
scraped the caterpillars off into a tin can, but in a short time they 
were just as thick again on the trunk. Some of our small fruit 
trees which were stripped at that time have not done much since. 
In that year (1890) if you went down the street with a sun um- 
brella, the caterpillars would drop down on it just like rain. 
(Mrs. E. E. Merrill, Lawrence Street.) 

In 1890 the street trees were badly injured by the gypsy-moth 
caterpillars. At night in the lindens in front of the house there 
was a noise like the gentle falling of rain. This was the noise of 
the caterpillars eating the leaves. (Mrs. Plummer.) 

In 1890 the whole place was full of gypsy-moth caterpillars. I 
think I scraped off half a peck of caterpillars from the sills of the 
house and from under the porch and from off the trees. (E. 
Loeffler, Lawrence Street.) 

The caterpillars did much damage in the Cross Street 
neighborhood. Says Mr. J. C. Miller : — 

The next year (1890) all the orchards in this section were com- 
pletely ravaged, and there was no fruit. The caterpillars simply 



ITS KAVAGES IN 1890. 43 

swarmed. I destroyed thousands of them by burning them with 
rags soaked in kerosene. I spent many hours in destroying them, 
but without making any perceptible difference in their numbers. 
They were over everything, and even got into the cellars. Some 
of my apple trees overhang my shop. In the evening when the 
caterpillars were liveliest the noise of their droppings falling on 
the shingles sounded like a steady shower. The gutter was brim- 
ful and running over with the droppings. 

Other sections of the town were afflicted in like manner : — 

In 1890 the apple trees on Fulton Street, Allen Court and 
Fountain Street were more or less stripped by the gypsy-moth 
caterpillars. Some of the apple trees were wholly denuded of 
their foliage, and the crops in some cases were lost. In some 
cases the limbs of the apple trees were killed by the ravages of 
the caterpillars. Even pear trees were sometimes badly eaten, 
and cherries also suffered. The leaves were completely destroyed 
on a little German willow in my yard. Rose bushes were very 
badly eaten. (S. F. Weston.) 

The large elm in front of my house was full of caterpillars in 
1890. The leaves were riddled and many were cut off. We would 
sweep up daily these bits and fragments of leaves which fell from 
the tree, but the next day the ground beneath would be littered 
with them again. This elm stands in front of the piazza, and 
many caterpillars came from the tree upon the house. They were 
so thick that we could not sit out on the piazza at all that summer. 
When we opened the front door they would string down all over 
one. The caterpillars at one time were so thick on a fence on 
Salem Street that I could have run my hand along the top rail and 
scooped them up. In this same year a maple tree standing in 
front of my house on Allen Court was badly eaten by the cater- 
pillars. You could hear them eating up in the tree. (Mrs. P. N. 
Ryder, Salem Street.) 

The gypsy-moth caterpillars were very numerous in 1890 on the 
Sparrell estate, No. 90 Main Street. . . . As evening came on 
you would see them everywhere on the ground heading for the 
trees. I have heard the noise of their feeding after dark. They 
kept coming into my yard from the yards of other people who paid 
less attention to destroying them. The leaves of the trees were 
just as if they had been scorched. One tree did not bear for 
several years. (Richard Pierce.) 

In 1890 I saw the caterpillars clustering in a mass on the body 
of an elm tree on South Street. I destroyed a great many of these 
by burning. (John Hutchins, 16 South Street.) 



44 THE GYPSY MOTH. 

Four years ago (1890) in the yards on the north side of Cotting 
Street the gypsy-moth caterpillars stripped the trees bare of their 
leaves. (John Cotton.) 

In 1890 I fought the pest. They came on to my place in mill- 
ions in April. The top of my fence rail would be covered with 
gypsy-moth caterpillars about as small as ants. ... I would 
take a brush broom and fight them perhaps an hour and a half. I 
would destroy them in the morning, and at noon would find as 
many more and clean them every one from my premises. At 
night I went through the same operation. I destroyed undoubt- 
edly millions. (W. W. Fifield, before the legislative joint stand- 
ing committee on Agriculture.) 

Residents of Edgeworth make similar statements : — 

The caterpillars were very thick on the house in 1890. When 
I went out of my side door I had to take a broom and brush them 
off the platform. I killed quarts that summer. At the next house 
they were just as bad. I swept them off above the door again 
and again, and they seemed to be back again as thick as ever in 
five minutes. An apple tree back of the house looked as if the 
leaves had all been burned. A few blossoms would come out and 
then wither away. I saw the gypsy-moth men burn the cater- 
pillars by the pailful. (Mrs. B. Wallace, West Street, Edge- 
worth.) 

In 1890 they were also plentiful, although not as thick as in 
1889. I got few if an} T apples in either year. The caterpillars 
were larger than your little finger. They would lie thickly to- 
gether on the trunks of the trees. In the evening they were so 
thick that they would drop down on the steps from above the 
door. (William McLaughlin, 107 Oakland Street.) 



THE WORK OF 1891. 45 



The Wokk of 1891. 

Appointment of the Second Commission. 
Governor Russell, having removed on Feb. 15, 1891, the 
salaried commission for the extermination of the gypsy moth, 
appointed another commission which organized as follows : 
Prof. N. S. Shaler of Harvard University, chairman, Francis 
H. Appleton of Peabody, secretary, both members of the 
State Board of Agriculture, and Hon. Win. R. Sessions, 
secretary of that Board. These gentlemen served without 
remuneration, accepting office with the understanding that 
legislation would be asked for with reference to placing the 
work under the control of the State Board of Agriculture, 
where they believed it properly belonged. The new com- 
missioners, having received information of their appoint- 
ment by the governor, lost no time in obtaining information 
from the best authorities in regard to the possibility of ex- 
terminating the moth and the best methods of procedure. 
They received their commission on March 4, and the same 
day held a conference at the office of the State Board of Ag- 
riculture, with several eminent entomologists. Many promi- 
nent men from the towns in the region infested by the gypsy 
moth were also invited to attend. Among those present were 
Professor Riley, entomologist of the United States Depart- 
ment of Agriculture, Professor Fernald, entomologist of the 
Hatch Experiment Station and of the Board of Agriculture, 
Mr. Samuel Scudder of Cambridge, Mayor Wiggin of Maiden, 
Chairman L. S. Gould of the selectmen of Melrose, Select- 
man W. C. Craig of Medford and W. A. Pierce of Arling- 
ton. The prevailing opinion of the entomologists was that 
recourse must be had to spraying with some of the arsenites 
in order to bring about the extermination of the moth. (See 
Appendix A for a report of the conference . ) 

Preliminary Arrangements . 
On March 12 the commissioners invited the members of 
the first commission to a consultation at the office of the 
State Board of Agriculture. Ex-Commissioners Rawson and 



46 THE GYPSY MOTH. 

Bradley met with the commissioners. They gave the com- 
mission such information as they possessed in regard to the 
habits of the moth, the methods used in controlling it and 
preventing its spread, its distribution and the extent of terri- 
tory infested by it. They also outlined on a map the territory 
known by them to be infested by the moth. (See map.) 
The " director of field work" who was appointed on that day 
was present and consulted with the commissioners in regard 
to taldng immediate steps for the eradication of the moth. 

In view of the conflicting opinions expressed in regard to 
the effectiveness of spraying as a means of extermination, 
it was decided to organize at once a force of men, and to 
destroy as many of the eggs of the gypsy moth as possible 
before the time for hatching arrived. The director took the 
train at once for Amherst, and visited the Hatch Experiment 
Station, where two days were spent in consultation with the 
entomologist, Prof. C. H. Fernald, and in examining insecti- 
cide appliances and the literature germane to the subject. 

It had been proposed by the commissioners that the di- 
rector secure the services of some of the students or gradu- 
ates of the Massachusetts Agricultural College as assistants. 
Through the good offices of Professor Fernald and Dr. H. 
H. Goodell, president of the college, in advising the students, 
several young men were induced to engage in the work 
of extermination. Some of these students had studied eco- 
nomic entomology under the guidance of the entomologist, 
and were especially fitted for the work in hand. From that 
time Professor Fernald's advice and assistance were always 
freely sought by the committee and director, and as freely 
given. All plans made were submitted to him for approval, 
and were only perfected after a careful consideration of his 
recommendations. The students who had been engaged were 
released in a few days from their college engagements, and 
on March 19 nine of them reported at the office of the State 
Board of Agriculture and received instructions. In the 
mean time the office and storehouse, which had been used by 
the first commission, had been opened, an inventory of prop- 
erty taken, and a hasty inspection made of the infested region 
by the director, in company with Ex-Commissioner Bradley. 
A few experienced men had also been employed. 



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THE WORK OF 1891. 47 

On March 20 actual work in the field was begun. The 
director and sixteen men visited the farm of Mr. Gilman 
Osgood in Belmont, which was the only locality in that town 
known by the first commission to be infested. It was then sup- 
posed that this was an isolated moth colony, and an attempt 
was made to stamp it out by gathering the eggs.* During 
the day, however, other colonies were found in Belmont. 

Tlie Work delegated to the Board of Agriculture. 
The commission of 1891 was superseded after a few weeks 
by the State Board of Agriculture, the act (chapter 210, 
Acts of 1891) placing the work in the hands of the Board 
being approved April 1 7 . The act follows : — 

[Acts of 1891, Chapter 210.] 

An Act to provide against depredations by the insect known 

as the ocneria dispar or gypsy moth. 

Be it enacted, etc., as folloics: 

Section 1. The state board of agriculture is hereby authorized, 
empowered aud directed to provide and carry into execution all 
reasonable measures to prevent the spreading and to secure the 
extermination of the ocneria dispar or gypsy moth in this Common- 
wealth ; and to this end said board shall have full authority to 
provide all necessary material and appliances, and to employ such 
competent persons, servants and agents as it shall from time to 
time deem necessary in the carrying out the purposes of this act ; 
and said board shall also have the right itself or by any persons, 
servants or agents employed by it under the provisions of this act 
to enter upon the lands of any person. 

Sect. 2. The owner of any land so entered upon, who shall 
suffer damage by such entry and acts done thereon by said state 
board of agriculture or under its direction, may recover the same 
of the city or town in which the lands so claimed to have been 
damaged are situate, by action of contract ; but any benefits 
received by such entry and the acts done on such lands in the 
execution of the purposes of this act shall be determined by the 
court or jury before whom such action is heard, and the amount 
thereof shall be applied in reduction of said damages ; and the 
Commonwealth shall refund to said city or town one-half of the 
amount of the damages recovered. 

* The attempt to eradicate the colony was not at that time successful, hut was ac- 
complished later. The moths were found that season in many localities in Belmont. 



48 THE GYPSY MOTH. 

Sect. 3. Said state board of agriculture shall have full 
authority to make from time to time such rules aud regulations in 
furtherance of the purposes of this act as it shall deem needful, 
which rules and regulations shall be published in one or more 
newspapers published in the county of Suffolk ; and copies of such 
rules and regulations shall be posted in at least three public places 
in each city or town in which said ocneria dispar or gypsy moth 
shall be found by said board to exist and a copy thereof shall be 
filed with the city clerk of each such city and with the town clerk 
of each such town ; and any person who shall knowingly violate 
any of the provisions thereof shall be punished for each violation 
by a fine not exceeding twenty-five dollars. 

Sect. 4. Said state board of agriculture shall keep a record of 
its transactions and a full account of all its expenditures under this 
act, and shall by its chairman or secretary make report thereof, 
with such recommendations and suggestions as said board shall 
deem necessary, on or before the fourth Wednesday in January, to 
the general court. 

Sect. 5. Said state board of agriculture shall establish the rate 
of compensation of any persons, servants or agents employed by 
it under this act. 

Sect. 6. Any person who shall purposely resist or obstruct said 
state board of agriculture, or any persons, servants or agents em- 
ployed by it under the provisions of this act, while engaged in the 
execution of the purposes of this act, shall be punished by a fine 
not exceeding twenty-five dollars for each offence. 

Sect. 7. It shall be unlawful for any person knowingly to bring 
the insect known as the ocneria dispar or gypsy moth, or its nests 
or eggs, within this Commonwealth ; or for any person knowingly 
to transport said insect, or its nests or eggs, from any town or city 
to another town or city within this Commonwealth. Any person 
who shall offend against the provisions of this section shall be pun- 
ished by a fine not exceeding two hundred dollars or by imprison- 
ment in the house of correction not exceeding sixty days, or by 
both such fine and imprisonment. 

Sect. 8. The said state board of agriculture may exercise all 
the duties and powers herein conferred upon said board, by and 
through its secretary and such members of said board as it may 
designate and appoint to have in charge, in conjunction with its 
secretary, the execution of the purposes of this act. 

Sect. 9. All moneys heretofore appropriated or authorized to 
be expended under the provisions of chapters ninety-five and one 
hundred and fifty-seven of the acts of the year eighteen hundred 
and ninety or by any other act, and not heretofore expended, are 



A NEW STATUTE. 49 

hereby appropriated and authorized to be expended by the said 
board in carrying out the purposes of this act. 

Sect. 10. All the property acquired and records kept under the 
provisions of said chapter ninety-five of the acts of the year eigh- 
teen hundred and ninety shall be delivered into the custody of said 
board, and said board is authorized to take, receive and use the 
same for the purposes of this act. 

Sect. 11. Chapter ninety-five of the acts of the year eighteen 
hundred and ninety is hereby repealed, but all claims for damages 
under said chapter ninety-five for entry upon and acts done on 
the lands of any person may be prosecuted, as therein provided, 
against the city or town wherein the lands entered upon are situate, 
and the damages shall be ascertained and one-half of the amount 
thereof recovered against any city or town shall be refunded to 
such city or town as provided in said chapter ninety-five. [Ap- 
proved April 17, 1891. 

A special meeting of the Board of Agriculture was held 
on April 28, and Messrs. Sessions, Shaler and Appleton 
were appointed a committee in accordance with the provi- 
sions of section 8 of the act. 

This committee organized on May 19, with the choice of 
Mr. Sessions as chairman and secretary. The committee 
continued the work which it had begun as a commission, 
confirming the appointment of the field directory and directed 
that the work being done in the field should be continued. 
A code of rules and regulations for the public was adopted. 
(See Appendix B.) At the time of appointment of the 
second commission there remained unexpended of the ap- 
propriation of 1890 the sum of $24,460.68. On May 19 
$11,003.22 only remained. On June 30 an additional ap- 
propriation of $50,000 was made by the Legislature. 

Mapping the Infested Region. 
In apportioning the territory to different inspectors, it was 
found necessary to make a hasty survey of the field and to 
plat it on maps of the towns known to be infested and those 
contiguous to them. These maps were divided into sections 
of such size as could be conveniently carried by the men 
engaged in field work. For convenience these sections 
were so drawn as to be bounded by town lines, streets and 



50 THE GYPSY MOTH. 

railways, or by natural bounds, such as streams and lakes. 
Each map was accompanied by a written description of the 
boundaries of the section which it represented. The work 
was done, under the supervision of the director, by Mr. 
J. O. Goodwin of Medford, an experienced engineer, well 
acquainted with the topography of the region. It was in- 
tended so to divide the region that each inspector or foreman 
could be held responsible for a certain tract or section with 
definite and well-marked boundaries. Each section in each 
town was numbered. Each inspector, on entering the field, 
was required to run the boundaries of the section allotted to 
him, and mark the section number prominently with white 
paint on fixed objects at each angle of the boundary. To 
avoid any possible confusion of lines, each inspector was 
also required to ' ' blaze " or mark the line with white paint 
wherever it was not otherwise easily distinguishable. When 
this system was extended into the towns farthest from the 
infested centre, it was not found necessary to divide such 
towns into sections on account of the comparatively small 
number of moth colonies found in them. They were treated, 
therefore, as sections, and an inspector with a gang of men 
was placed in charge of each. If, however, it was found, on 
close inspection, that a town that had not been " sectioned" 
was badly infested, and would require several gangs of men, 
it was then " sectioned." Each inspector was required occa- 
sionally to sketch maps ; also to locate and mark infested 
localities on section maps, and to make such additions to the 
maps as were from time to time necessitated by the con- 
struction of new streets or railways in the infested towns. 

Organization and Instruction of the Field Force. 

Whenever suitable men could be found they were added 
to the force. Some of the most capable men of the force 
of 1890 were re-employed. Others, whose previous expe- 
rience in field study in entomology or kindred sciences had 
fitted them for careful observation, were engaged and trained 
to act as inspectors. 

When field operations were commenced the eggs of the 
moth were the only living form of the pest. The men 
were taught how to recognize and destroy them, and to 



THE INSTRUCTION OF EMPLOYEES. 51 

distinguish them from those of native moths. They were 
taught to observe all evidences of the presence of the gypsy 
moth, and were requested to secure by personal observation 
as the season advanced all possible information in regard to 
its habits. When the inspectors had gained sufficient knowl- 
edge to enable them properly to instruct others, laborers 
were employed, and each inspector was put in charge of a 
few men, over whom he was given full authority with in- 
structions to recommend the discharge of anv man who 
proved inefficient or untrustworthy. Each inspector was 
given a short time in which to instruct his men by engaging 
them in practical work in the worst-infested portions of 
Maiden and Medford. Then a section (indicated by a map) 
was allotted him, with instructions to inspect it and destroy 
the eggs therein. When eggs were found on a tree or other 
object, certain characters were marked upon it with white 
paint, and the locality was designated on the map. 

As the season advanced and the extent of the region occu- 
pied by the moth became known, it was found necessary to 
employ two hundred and fifty men, and distribute them over 
this region. It became evident that it was impossible for 
one man to keep the entire field under supervision. Six 
superintendents were then selected from among the most 
efficient of the inspectors. Each of these was required to 
supervise the work in several towns. When spraying began, 
one man was placed in charge of tools and supplies, including 
spraying apparatus and teams. A code of rules and regula- 
tions was prepared and printed early in the season, and copies 
were distributed among the employees. (See Appendix B.) 

Daily Reports and Records. 
Each inspector was instructed to make out daily a written 
report of the work done by himself and men, and to incor- 
porate in these reports his observations on the habits of the 
moth and its parasites, notes on its distribution and all 
useful information acquired by him in regard to the moth or 
methods of eradicating it. In these reports the number of 
trees, buildings, fences, walls, hedges and other objects 
inspected daily was recorded ; the number of each on which 
the moth was found ; the number of each form of the moth 



52 THE GYPSY MOTH. 

found and destroyed by hand on each estate ; the number of 
trees cut or treated by banding, burlapping, cementing or 
scraping; and the number of acres of brush or woodland 
burned over. Mention was also made of any work left 
unfinished for the time being, or thought to be necessary 
later. Whenever the moths were found in a locality not 
before known to be infested, the inspector was required to 
sketch on the day's report a map of the locality, marking the 
colony in a manner prescribed and in such a way that it could 
be found at once by one not familiar with the place. 

The name of the inspector appears on each of his daily 
reports, together with the names of his men. The number 
of hours per day that each man works is also recorded on 
the report. The reports are filed, and by them it is pos- 
sible to determine which inspector and men are responsible 
for any work done at any point on a given day in any year, 
and to fix the responsibility should any omission of duty or 
any misdemeanor occur on the part of the employees. An 
account with each infested estate is kept in the office in 
books known as " section books." 

The section books in which the records of field work are 
kept now number seventy-eight, of one hundred pages each. 
On the first page of each book the bounds and a general de- 
scription of the section are given, and the work done in it 
and the results attained for the year are recorded on the 
succeeding pages. There is also a " blue print " map marked 
in such a way as to designate each infested locality. (See 
Appendix C.) It is possible by consulting these books to 
learn how much work has been done on each infested estate, 
how many units of each form of the moth have been killed 
by hand, and whether the moth has been eradicated from 
that locality or not. There is thus kept a complete record 
of the progress made. 

The Spring Inspection. 
An inspection of the infested region was begun in March, 
with a view of determining its extent. This inspection com- 
menced in Medford and Maiden near the centre of the region, 
and extended to the surrounding towns as the organization 
of the force was perfected and its size increased. Each 



THE SPRING INSPECTION. 53 

inspector was first sent with his squad to inspect a section in 
one of the towns then known to be infested. He was in- 
structed to inspect the entire territory within the boundaries 
of the section, and destroy all the eggs found therein. 

It was at once seen that the moth was most numerous 
along the thoroughfares. A few of the most expert men 
were sent into the towns nearest Maiden and Medford to 
examine the roadsides and mark any colonies found. These 
men speedily found the moth in Lexington, Winchester, 
Wakefield, Melrose, Revere and Saugus, thus greatly adding 
to the knowledge of the extent of the infested region. Work 
was hurried forward in all these towns. The eggs were cut 
or scraped from the trees with knives, gathered into cans 
and burned with oil in small stoves made for the purpose. 
Rubbish and undergrowth containing eggs were also de- 
stroyed by fire. As much more territory was found infested 
than was at first estimated, it was found impossible to secure 
and train men enough to make a thorough search of the entire 
region and destroy all the eggs before hatching time. As it 
was necessary to determine as soon as possible how far the 
moth had become disseminated, a portion of the work in 
Maiden and Medford was given up, and the men who had 
been engaged in destroying eggs there were sent into the 
outlying towns. For this reason, when the eggs began 
hatching a considerable area yet remained in a few of the 
inner towns where the eggs had not been destroyed. Many 
eggs which had been scattered about, both by the work of 
the first commission in the fall of 1890 and by the work in 
the spring of 1891, hatched, and caterpillars began to appear 
in large numbers over a wide area. When work was begun 
the time remaining for this inspection and egg killing did 
not exceed six weeks, as the eggs begin hatching before 
May 1. Yet in that short time the moths had been found 
far beyond the utmost limits of the region previously known 
as infested. 

The Condition in which the Infested Region was found in 

1891. 
When work was begun by the second commission the eggs 
of the moth were found in great numbers upon the trees in 



54 THE GYPSY MOTH. 

certain localities in which little work had been done in the 
fall of 1890 by the first commission. In some of these 
places the bark of the trees was so covered with egg clusters 
that it presented a yellowish appearance. This was the case 
only in parts of Medford and at a few points in Maiden. 
Wherever the first commission had worked the previous 
autumn, few egg clusters were found on the trees. It was 
decided, however, to make a thorough search of all localities 
wherever it was practicable. With this in view, the base 
boards of fences were taken off, plank walks raised, the 
steps of houses torn up and cellars and buildings entered. 
In such places the eggs of the moth were found concealed 
in great numbers. In some cases quarts of eggs were taken 
out from beneath piazzas or flights of steps. Many eggs 
were also found in some cellars. As the inspection pro- 
gressed, a few badly infested localities were found in other 
towns and many eggs were destroyed. In most of these 
towns the moths had not been colonized long enough to 
become numerous, but were found in isolated colonies along 
the roads. Such inspections as were made of woodlands 
revealed in most cases comparatively few colonies, most of 
them small and isolated. 

A careful estimate has been made from the daily reports of 
inspectors, which shows the number of egg clusters destroyed 
during the first six weeks of 1891 to be 757,760. The num- 
ber of eggs contained in these clusters would probably be 
from three to five hundred millions. 

The Enforcement of Police Regulations. 
When in May the caterpillars were seen to be dropping 
by their threads from the trees upon passing teams and 
vehicles, it was deemed necessary to do something to check 
their distribution in this manner. The method (used by the 
commission of 1890) of guarding the roads leading out of the 
worst-infested district was tried. The police were required 
to inspect all horses and vehicles going out of the infested 
district, record all facts regarding their destination, and 
destroy any caterpillars found upon them. They were also 
required to enforce the regulations of the department in 
regard to the hauling of hay or manure without covers, and 



SPRAYING. 55 

other matters relating to team traffic. The police outposts 
were inspected by Professor Shaler of the committee in 
charge of the work, by the director and by the superintend- 
ents, and it was soon seen that the method was impracti- 
cable. A perfect cordon could not be maintained, and the 
results obtained were not proportionate to the expense 
incurred. At the end of two weeks the plan was abandoned. 
In the mean time some good had been done by destroying 
caterpillars found on vehicles, and by gaining a knowledge 
of the destination of the teaming between badly infested 
localities and towns outside of the known infested district. 
This knowledge was utilized in the fall inspection. 

Spraying . 

In April the director's office was removed to Maiden, at a 
point near the centre of the infested region and having better 
railway communications with the surrounding towns. More 
commodious rooms were here secured, and experimenting 
with insecticides was begun. Most economic entomologists 
concurred in recommending spraying with arsenical poisons 
for killing all leaf-eating larvae. Following such advice, ex- 
periments with arsenites were begun. An early supply of 
gypsy-moth larvae was obtained by artificial hatching, and 
the experimental work was continued during the spring and 
summer, the experiments with Paris green giving the best 
results. In the laboratory it was found that young cater- 
pillars, fed upon plants to which this poison had been 
properly applied, died within a few days. In later experi- 
ments it was noticed that a considerable proportion of the 
larger caterpillars survived. In the experimental work in 
the laboratory, no injury to the foliage was observed when a 
mixture of one pound of this poison to one hundred and fifty 
gallons of water was used. Glucose was also added to 
retain the poison upon the leaves. 

When it became evident that Paris green was the most 
effective of the arsenites, preparations were made for its use 
on an extensive scale. In the first part of May teamsters 
were employed, and twenty spraying outfits were put upon 
the road in Medford. The number of men and teams was 
soon found to be insufficient. Ten additional spraying out- 



56 THE GYPSY MOTH. 

fits were purchased, and the capacity of each was doubled 
by improved appliances. Each outfit with the accompanying 
squad of men was under the immediate charge of an inspect- 
or. When the apparatus had been tested and the men had 
gained the skill necessary for its intelligent use, the entire 
force was sent to the periphery of the region then known to 
be occupied by the moth and ordered to work toward the 
centre. The infested area was thus sprayed until the middle 
of July. At that date numbers of caterpillars were fully 
grown and had stopped feeding ; some had pupated and 
others were wandering from tree to tree. Other means 
were then used for the destruction of both caterpillars and 
pupae. * 

Considerable opposition to the use of Paris green for 
spraying was manifested by many people living in the in- 
fested towns. A mass meeting of opponents of the spraying 
was held in Medford. One citizen, who attempted to cut 
the hose attached to one of the spraying tanks, and threat- 
ened with violence the employees of the Board who had 
entered upon his land, was arrested and fined. Others neu- 
tralized the effects of the spraying by turning the garden 
hose upon trees and shrubs that had been sprayed, and 
washing off the solution. The opposition to the spraying 
affected the results of the work unfavorably to a consider- 
able extent. In June a bulletin of information was issued 
by the State Board of Agriculture, containing quotations 
from Professor Riley and other economic entomologists as to 
the lack of danger to man or beast attending the use of Paris 
green. This bulletin was distributed freely among the people 
of the district, but it failed to allay the popular prejudice 
against the spraying. 

During the spraying season Professor Eiley and Mr. Sam- 
uel Henshaw (at that time an entomological agent of the 
United States Department of Agriculture) visited the dis- 
trict and inspected and criticised the operations in the field. 

It became evident before the close of the season that the 
spraying, while reducing the numbers of the moth, could 
not be relied upon as a means of extermination, for many 
caterpillars survived its effects. In June, when the cater- 
pillars had reached the fourth molt and begun to cluster in 




PLATE X. Trees stripped by caterpillars of the gypsy moth, Arlington, 
Mass. From a photograph taken July 9, 1891. 



THE SUMMER WORK. 57 

cavities of the tree trunks and in other hiding places, they 
were destroyed by spraying with insecticides which killed 
them by contact. The arsenites have no effect when used 
in this way. Burlap bands were also placed about the trees 
to serve as artificial hiding places for the caterpillars, and 
many were destroyed beneath the bands. This method was 
so successful that it was generally adopted, and more than 
sixty-eight thousand trees were banded during the season. 

Entomological Work. 
On June 18 Prof. Charles H. Fernald was appointed en- 
tomological adviser to the committee. Arrangements were 
made by which he could give a portion of his time to the 
work, and one of his assistants, Mr. E. P. Felt, was em- 
ployed in making observations and experiments. Professor 
Fernald critically examined the field work, reported thereon, 
and made frequent subsequent visits of inspection to the in- 
fested territory, directing the experiments and giving advice 
concerning the work in the field. At his suggestion the in- 
spectors were directed to watch for parasites of the moth in 
its various stages. Several parasites were discovered. All 
dead pupre found during the season in the central towns were 
collected and preserved, in order that the parasites preying 
upon them might be obtained. The dead pupae found in the 
outer towns of the infested territory were left on the trees, 
that the parasites might escape from them and continue their 
work. The inspectors were encouraged in their observations 
on the habits and life history of the moth. The feeding 
habits were made the subject of especially careful observa- 
tion, and all the information thus gained was recorded and 
tabulated for future use. 

Numbers and Destructiveness of the Moth in the Summer of 

1891. 

Though a great number of eggs had been burned in the 
spring, and thousands of caterpillars had been killed by 
spraying, burning, burlapping and other means, they were 
still so numerous in the summer of 1891 that some dam- 
age was done in certain localities. A few trees in some 
orchards in Maiden and Medford were almost defoliated. 



58 THE GYPSY MOTH. 

In one case in Medford three apple trees which had been 
sprayed were only saved from defoliation by the use of con- 
tact insecticides. Two bushels of dead larvae and pupa? 
were gathered from the ground beneath these trees. The 
injury was most severe wherever a locality had been over- 
looked in the spring inspection, and numerous eggs thereby 
allowed to hatch. Early in June a colony of moths was found 
in a small grove of trees in Arlington. Although the trees 
were sprayed twice with a mixture of Paris green and water 
(two pounds to one hundred and fifty gallons), the foliage 
was entirely destroyed, and the caterpillars then spread in all 
directions through the fields, eating the grass as they went. 
In spite of all that was done to stay them, many reached the 
woodland one-eighth of a mile away. Others, having de- 
foliated the trees, clustered in masses on the trunks and 
branches and about and upon the rocks beneath. These 
were finally destroyed by fire. After the larvae upon the 
trees and undergrowth had been destroyed, the stones 
beneath the trees were overhauled and pupae were gathered 
at the rate of about eleven hundred per hour per man. 
There were similar but less destructive outbreaks in other 
parts of Arlington, and in Winchester, Chelsea and Melrose, 
but the one of greatest magnitude occurred in Swampscott. 
This was beyond the range of the spring inspection, and the 
colony was found in July by an inspector who had been sent 
out to search that region for caterpillars. It was situated on 
a hillside near Humphrey Street. There were several trees 
infested in a yard and others in a small orchard on a hillside 
in the rear. Back of the orchard was a pasture somewhat 
overgrown with trees and shrubs. On the east and extend- 
ing over the highest point of the hill there was woodland 
composed of a great variety of trees, both deciduous and 
coniferous. Beginning at the edge of the orchard a dense 
undergrowth or jungle of creeping vines and bushes extended 
into the woodland. 

When this colony was first found the caterpillars had be- 
gun eating the foliage of nearly all species of trees and 
plants in the immediate vicinity of the house and outbuild- 
ings, and were fast spreading into the woodland and pasture. 
A gang of men was sent to the spot with a spraying tank 



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RAVAGES OF 1891. 59 

which was set on a hill near by. Water was drawn by a 
hose from a near hydrant, and the trees, shrubbery and vege- 
tation in the whole neighborhood were sprayed heavily with 
Paris green. As this did not appear to check the ravages 
of the larva?, the locality was resprayed at once. Within a 
few days of the time of the last spraying nearly every green 
leaf on several acres was eaten by the caterpillars. This 
destruction continued incessantly, and the injury spread in 
all directions. Six gangs of men were despatched at once 
with orders to surround the infested locality and work 
from the outside to the centre, and burn with an oil spray 
all undergrowth and everything on which the larva? could 
feed, destroying at the same time with the fire all the cater- 
pillars possible. This treatment effectually checked their 
diffusion, thereby preventing further injury. The pupa? 
were raked off the worst-infested trunks and burned or other- 
wise destroyed. 

Mr. C. R. Drew of Medford, writing of the numbers of 
the moth in 1891 at his place, says : — 

There seemed to be almost millions of gypsy-moth caterpillars 
in 1891 at the corner of Fountain and Salem streets, where I then 
lived. They very nearly destroyed a blue pearmain apple tree. 
It bore no fruit that year. This tree blossomed out in the spring, 
but when it began to leaf out the caterpillars attacked it and every 
vestige of green disappeared. It looked as if fire had run through 
the tree. Several sweet-apple trees were also badly eaten. You 
could hear the noise of the caterpillars eating in the trees at dusk. 
They were so thick that you could scrape them off anywhere. They 
crawled all over the concrete, and we crushed them as we walked. 
We had seats on the grass under the trees, but we could not sit 
there because the. caterpillars dropped down so thickly. It was 
possible daily to gather a half water-bucketful of them, but the 
next day they would be just as bad. 

Mr. L. B. Sanderson, an employee of the Board, re- 
ports : — 

At Mr. Drew's yard we got one day twenty-two quarts of catei*- 
pillars. 

Such cases, however, were exceptional, for the greater 
portion of moths in the worst-infested places were destroyed 



60 THE GYPSY MOTH. 

by the agents of the Board of Agriculture before serious 
injury had been done. 

Fall Inspection and Egg Gathering. 
In September, when the moths had laid their eggs, the 
force of men was reduced. The most expert employees 
were retained, and these were engaged in destroying eggs 
in the worst-infested districts of Maiden and Medford, until, 
by practice, they had become efficient in this sort of work. 
As soon as the leaves had fallen from deciduous trees, the 
men were sent into the towns and cities beyond the region 
which the moth was known to occupy, and the inspection, 
which had been interrupted in the spring by the growing 
leaves, was continued. An inspector was assigned to each 
town, and instructed to inspect that town hastily, and if 
moths were found there to proceed immediately to the next, 
and so on until a wide belt of territory around the infested 
region had been inspected in which no moths could be found. 
Eighteen towns and three cities outside of the known infested 
region were thus inspected in November and December. 
The moths were found in each of the cities and in four of the 
towns, and it was reported to the Legislature that whereas 
in the spring the moths had been supposed to be confined to 
a few towns, they were now known to be in thirty townships, 
as follows : Arlington, Belmont, Beverly, Brighton (Ward 
25, Boston), Cambridge, Charlestown (Wards 3, 4 and 5, 
Boston), Chelsea, East Boston (Wards 1 and 2, Boston), 
Everett, Lexington, Lynn, Lynnfield, Maiden, Marblehead, 
Medford, Melrose, Peabody, Reading, Revere, Salem, 
Swampscott, Saugus, Somerville, Stoneham, Waltham, 
Wakefield, Watertown, Winchester, Winthrbp and Woburn. 

Results of the Work. 
During the season of 1891 the work carried on was effective, 
inasmuch as it destroyed all the large colonies of the moth, 
and protected the fruit and shade trees of the State from 
further injury. The spraying and other treatment of the 
trees redoubled the fruit crop of the district. The measures 
used disposed of the annual increase of the moth, and reduced 
the numbers originally found by about ninety per cent. 



RESULTS OF THE WORK OF 1891. 61 

The inspection of 1891 gave a closely approximate idea of 
the size of the region infested by the moth, as it has not 
since been found in any numbers or to any distance outside 
of the boundaries then laid down. As the work was neces- 
sarily hurried in order to complete it by Jan. 1, 1892, so 
that the size of the infested region might be reported to the 
Legislature, many small colonies were overlooked. Thus, 
though the approximate area of the infested region was 
determined, its condition was not thoroughly known at the 
close of 1891. It was seen early in the season that the 
appropriation made would not be sufficient to exterminate 
the moth in one year, but it was thought that $75,000 was 
all that could be used to advantage until such time as the 
exact area and condition of the infested region could be 
ascertained. 



62 THE GYPSY MOTH. 



The Work of 1892. 

On the first of January, 1892, there remained of the 
appropriation of 1891 the sura of $5,213.13. This could 
have been used to good advantage before January 1, but it 
was thought to be of more importance to retain it, so that 
the most expert men might be kept at work until such time 
as another appropriation would become available. The 
nucleus of an organization was thus maintained during the 
winter. Early in January, 1892, when the Legislature con- 
vened, the State Board of Agriculture by its secretary made 
a report recommending an appropriation of $75,000 for the 
year. Though the money available in 1891 had proved in- 
sufficient to maintain as large a force as was needed to obtain 
the best results, the committee deemed it unwise to recom- 
mend more than $75,000 for the work of 1892. The 
experience of 1891 had determined that spraying with 
arsenical insecticides (the method which had been most 
strongly recommended by the best authorities) was a failure 
as a means of extermination. The experimental work of the 
first year had not resulted in providing a better insecticide, 
and further experiments were necessary. Again, much 
difficulty had been experienced in securing efficient and 
trustworthy men. It was evident that a large portion of 
another season must be occupied in selecting and training a 
body of men which could be used in organizing a larger force. 

Although the moths had been found scattered over a region 
of two hundred square miles, there was considerable doubt as 
to whether the extent of the infested area had yet been 
determined. Though the outlook was not altogether en- 
couraging, nine-tenths of the moths in the region found 
infested had been destroyed, and there was no immediate 
danger from them so long as they were kept under control. 
The committee were confident that the moths could be con- 
trolled and their numbers at the same time still further 
reduced with the amount of money recommended, while in 
the mean time experimental work could be carried on to 
determine the policy for the future. 



THE WORK OF 1892. 63 

Only forty of the most efficient men had been retained 
from the field force of 1891, and by reason of delay in 
granting the appropriation, the committee were obliged to 
discharge them all. Some of the most capable of these men 
soon obtained employment elsewhere, and this loss reduced 
the efficiency of the working force. Very little work was 
accomplished during the month of February. Finally, on 
March 1, an act authorizing an appropriation of $75,000 was 
passed by the Legislature. This made it possible to make 
arrangements to resume field work, although unseasonable 
snow-storms still further delayed the spring inspection. The 
old method of scraping the eggs from the trees and burning 
them was discarded, and the eggs were left on the trees and 
treated with acids or creosote. The scattering of eggs was 
thus avoided. 

The experimental work of 1891 resulted in the trial in the 
field in 1892 of several new insecticides. None of them, 
however, proved generally effective, although bromine and 
chlorine were useful in destroying eggs in hollow trees. 

Professor Fernald had recommended in December, 1891, 
' ' that the nests of the gypsy moth hereafter gathered be pre- 
served in such a way that the eggs of parasites that may have 
been laid in such eggs of the gypsy moth be allowed an 
opportunity to develop into the perfect insect." This plan 
was put into operation early in 1892 in the towns of Maiden 
and Medford. All the eggs gathered were taken to a central 
point in each town, and were there kept in a closed case until 
all were hatched. As only a single specimen of an egg 
parasite was obtained in this way, the plan was aban- 
doned. 

Owing to the lateness of the appropriation, which caused 
delay in examining and employing men, and the unseason- 
able weather, it was impossible before hatching time to make 
a thorough inspection of the infested region, but an attempt 
was made to destroy all egg clusters found along the roads. 
This was done to prevent the spreading of the caterpillars. 
This method was intended to take the place of police out- 
posts on the roads. It was a preventive measure, for, if the 
eggs were removed from the trees, there would be no cater- 
pillars to spin or drop down upon the passing vehicles and 



64 THE GYPSY MOTH. 

teams. It was in this manner that the moths had been dis- 
tributed in former years. Wherever large trees near high- 
ways had been cleared of eggs, they were banded with tree ink 
or with "Raupenleim" ("insect lime") to prevent the cater- 
pillars ascending them from the ground. This was intended 
to keep the moth out of such trees for the season. Very 
little spraying was done during 1892. Two spraying outfits 
were kept busy for a short time, and were sent from place to 
place wherever the caterpillars appeared in considerable num- 
bers. The trees in such localities were sprayed when the 
caterpillars were small, and many of the latter were killed. 
This served to lessen the dissemination. The method of 
burlapping trees was used in place of spraying, and was ex- 
tensively employed over most of the infested region. The 
force of employees, numbering two hundred and thirty-four 
during the spring inspection, was afterwards reduced, but was 
again increased during the inspection of burlaps. The ap- 
propriation was not sufficient, however, to provide enough 
men to thoroughly examine the burlaps. Notwithstanding 
this disadvantage, burlapping and hand-killing during the 
summer disposed of nine-tenths of the gypsy moths in the 
places known to be infested, and in many localities they 
were exterminated by this work alone. 

During the fall inspection an attempt was made to search 
the country thoroughly, but again the lack of money was 
felt, and it was found necessary soon after the first of Sep- 
tember to discharge a large proportion of the force. Only 
about forty of the most expert men could be retained. It 
was impossible with this number of men to make a thorough 
examination of the entire infested region. A great deal of 
effort was devoted to determining whether the moth had 
spread farther than had been reported in 1891. A consider- 
able proportion of the later expenditure of the year was thus 
used in the towns immediately surrounding the infested 
region. But the moth was not discovered in any other 
towns in 1892. 

The infested region was so well covered by the distribu- 
tion of the force that no serious outbreak of the moth 
occurred in 1892. Enough had now been learned of the 
condition of the infested territory to convince the committee 



LARGER APPROPRIATIONS NEEDED. 65 

that larger appropriations were needed. They believed that 
they had now learned by experience how to eradicate the 
moth. A large number of colonies had already been exter- 
minated, and it had been proved that the moths could be ex- 
terminated wherever they were found. The committee in its 
annual report to the Board recommended that an appropri- 
ation of $165,000 be granted for the work of 1893. The 
report was accepted by the Board, and presented to the 
Legislature of 1893. The report begins as follows : — 

In presenting the report of the gypsy moth department of the 
State Board of Agriculture, in accordance with the provisions of 
chapter 210, Acts of 1891, the committee desires to call attention 
to the fact that this effort to exterminate the Ocneria dispar is the 
first attempt on a large scale ever made in this Commonwealth to 
destroy a species of insect, consequently there was no trustworthy 
experience to guide the work. As it was an imported insect, its 
habits and peculiarities in this country had to be ascertained 
before the most effective methods of destruction could be deter- 
mined. 

Much of the work that has been done may be considered as in 
a measure experimental. As we have become more familiar with 
the extent of the territory invaded by the moth, the magnitude of 
the task has become more apparent. When the Legislature made 
the first appropriation, it was supposed that the moth occupied 
but a small part of one town. Careful inquiry has shown that it 
infests thirty cities and towns. From our observations we have 
no doubt that it was in nearly everyone of these localities in 1890, 
when the campaign of extermination was commenced.* 

During the year much had been done toward inspecting 
the towns on the borders of the infested district. Of this, 
the committee reports : — 

Much effort, involving a large expenditure, has been devoted to 
the inspection of territory outside the infested limit. Numerous 
letters have been received from different parts of the State and 
from adjoining States, to the effect that supposed gypsy moths 
bad been found. These notices have in all cases led to an inspec- 
tion of the suspected locality. The towns just outside those 

* Report of the State Board of Agriculture on the Extermination of the Gypsy 
Moth, January, 1893, page 5. 



66 THE GYPSY MOTH. 

infested have also received some attention, but in no case has the 
gypsy moth been found outside of the limits reported last year.* 

Such expert men as could be spared from other work had 
been detailed to examine as much as possible of the large 
wooded region in the infested territory, so that its condition 
might be reported on as fully as possible to the Legislature. 
The woodland was found to be more or less infested, but its 
exact condition could not be determined, owing to a lack of 
money and trained men. On what was known of its condi- 
tion, the committee based their recommendation for a larger 
appropriation, setting forth their plans in regard to it in the 
following words : — 

We desire to present to the Legislature the state of the problem 
and various plans for solving it, with an estimate of the cost of 
each class of work for the next year. There are large areas of 
woodland in the infested towns. There are points in these forested 
districts known to be infested. There are probably other points 
where colonies have been established, and possibly many such. 
The dense growth of the underbrush in this woodland, and the 
thick carpet of dead leaves on the ground, make perfect inspection 
almost impossible. There are about four hundred acres of this 
woodland, which will, if it is allowed to remain, continue to be an 
uncertain element in our problem. 

If the timber could be felled and burned on the ground during 
the winter and early spring, and the ground carefully burned over 
twice during the summer, that element would be eliminated. We 
estimate the cost of this work at $125 per acre, or a total of 
$50,000 ; but we are confronted with the fact that most of the 
forest is situated in Medford, Maiden, Arlington, Melrose, Win- 
chester and Stoneham, and that much of it is valued for prospective 
parks. Its destruction would be considered a calamity by the in- 
habitants of these places. 

We believe that with sufficient means, and in several years' 
time, these forest lands can be cleared of moths without destroy- 
ing the timber. To accomplish it all the underbrush and all the 
decayed and worthless trees must be cut and destroyed by fire, 
the ground burned over, and the whole carefully inspected at least 
twice each year. Burlaps must be placed wherever the moth 
appears or has been found previous to the clearing up. The latter 

* Report of the State Board of Agriculture on the Extermination of the Gypsy 
Moth, January, 1893, page 6. 



A LARGER APPROPRIATION URGED. 67 

plan will in the aggregate cost more than the former, but, as the 
work need not necessarily be all clone at once, and as it could be 
done in connection with the other work of the department, utilizing 
the time of the men in the winter and early spring, it may be the 
best plan to pursue.* 

The conimittee had undertaken to secure as full informa- 
tion as possible in regard to European experience with the 
gypsy moth and the methods used in Europe to combat it, 
as well as the probabilities regarding its future in this coun- 
try and the destruction which would be caused by it if it 
were allowed to spread unchecked except by individual 
effort. The information thus gained was tersely embodied 
in the report to the Legislature, as a warning to show what 
might be expected in the future. Tables of damage done to 
crops in the United States by insects were presented in the 
field director's report. The entomologist, who had at first 
grave doubts of the possibility of complete extermination, 
stated in his report that he had been led to believe that such 
a thing was really possible, provided the work were continued 
for several years w T ith sufficient appropriations to keep the 
entire territory under careful supervision. The State Board 
of Agriculture, approving the action of its committee, urged 
that the appropriation recommended be granted, and that 
every effort be made at once to rid the State of the pest. 



* Report of the State Board of Aguculiure on the Extermination of the Gypsy 
Moth, January, 1893, page 7. 



68 THE GYPSY MOTH. 



The Work of 1893. 

Pursuant to the recommendation of the State Board of 
Agriculture, the joint standing committee on agriculture of 
the Legislature of 1893 reported a resolve appropriating 
$165,000 for the extermination of the gypsy moth. While 
this resolve was before the committee on finance, the com- 
mittee on the extermination of the gypsy moth voted "to 
suggest to the committee on finance that they advise the 
appointment of a committee of three or five of the Legislat- 
ure to investigate the work of the committee of the Board 
of Agriculture during the year 1893, and make such a report 
to the next Legislature as in their judgment seems wise." 
No such committee was appointed. Members of the Board 
of Agriculture appeared before the committee on finance to 
advocate the appropriation of $165,000. Expert entomol- 
ogists and many citizens of the infested district also appeared 
or sent communications, advising that every possible effort 
be made to exterminate the moth, and that the Board of 
Agriculture be given the full appropriation. But the finance 
committee reported in favor of reducing the amount to 
$100,000. 

There was considerable delay in granting this appropria- 
tion, and, as the money remaining from 1892 was nearly 
exhausted, it became necessary to suspend all field work. 
While the work was thus suspended and the committee was 
awaiting an appropriation, as in 1892, several of the most 
experienced men obtained other situations. This loss reduced 
the efficiency of the force. By reason of the delay several 
weeks of the best working time of the year passed unutilized. 
On April 12 an appropriation of $100,000 was made by the 
Legislature. A resolve was also sent to Congress by the 
Legislature, asking for $100,000 additional to continue the 
work. This resolve got no further than the committee room, 
and was never entertained by Congress. 

As soon as the appropriation became available, field work 
was again commenced. The force of men was increased as fast 
as was compatible with their proper examination and training. 



VISITS FROM ENTOMOLOGISTS. 69 

The short time remaining before egg-hatching time was util- 
ized in destroying eggs in the worst- infested towns, and 
searching for them in the outer and less-infested towns. 
The trees in infested localities were banded with burlaps. 
During the summer the burlaps in the outer towns were 
visited daily, and the trees were occasionally examined, 
both by the regular men and by special inspectors. By 
this means the moth was almost completely eradicated 
from such towns, and in some of these towns no eff2;s were 

7 Co 

found during the autumn. Owing to the insufficiency of the 
appropriation and the consequent lack of men, the burlaps 
in the central towns were not as often visited. As the effec- 
tiveness of this method depends on daily visits to the bands, 
the results here were not as satisfactory as in the outer towns, 
but the moths were held in check and somewhat reduced in 
numbers. 

During the summer an experiment in trapping the male 
moths was tried, with a view of determining whether the 
number of fertile eggs would be decreased thereby. Experi- 
ments with insecticides during the season proved the useful- 
ness of a new insecticide, — arsenate of lead. Raupenlehn 
was used to a considerable extent in 1893, as it was during 
1892, but was not found so effective, perhaps by reason of 
its inferior quality. 

In May the committee voted to request Professor Fernald 
to invite six of the most prominent entomologists in the ad- 
joining States to visit the infested region and critically 
examine the field and office work, and report the results of 
their observations. Prof. Clarence M. Weed, D.Sc, of the 
New Hampshire State College, Dr. A. S. Packard of Brown 
University, Dr. J. A. Lintner, State entomologist of New 
York, Professor John B. Smith of Rutgers College, State 
entomologist of New Jersey, and Dr. H. T. Fernald, profes- 
sor of zoology at the Pennsylvania State College, visited the 
territory in the summer, examined and criticised the work, 
and reported upon it. Their reports will be found in Apr 
pendix D. The recommendations of these entomologists 
were carefully considered by Professor Fernald and the 
director, who reported to the committee that the suggestions 
made should be carried out as far as practicable. 



70 THE GYPSY MOTH. 

With the increased force provided by the larger appropria- 
tion, it was possible to accomplish in 1893 much more than 
had been done in former years. Every effort was made to 
determine how far the moth had spread, and whether it had 
passed beyond the limits of the region known to be infested 
in 1891. Careful inspection was made of a large number of 
towns on the borderline of the infested region, which resulted 
in small colonies being found in three places just outside the 
line drawn in 1891. It was evident that these colonies had 
been in existence for several years, even before the work of 
extermination was begun. One other colony was found at 
Franklin Park in Boston. This had evidently been growing 
for at least four or five years. Efforts were made to exter- 
minate the moth from the outer belt of towns of the infested 
region. These efforts were so successful that at the end of 
the year no form of the moth was found in any of the follow- 
ing towns: Beverly, Brighton, Burlington, Charlestown, 
Danvers, Lynnfield, Marblehead, Reading, Waltham and 
Watertown. 

During the season more than eight hundred colonies of 
the moth had been exterminated. But a detailed search of 
certain portions of the woodland in the infested region, which 
had been suspected but had not been known before to be 
infested, revealed small colonies scattered here and there, 
indicating that while a large proportion of the force had 
been concentrated upon the outer towns with a view to 
exterminating the moth there, the problem had been increas- 
ing from within by the spreading of the moths into the 
woodlands in the interior towns. 

The Board of Agriculture in its annual report on the 
gypsy-moth work to the Legislature again advised that 
everything possible be done to exterminate the moth, and 
recommended that $165,000 be appropriated for the work 
of the ensuing year. The magnitude of the work and the 
possibility of destruction to the forests were stated, and 
the plans for dealing with the moth in the woodland were 
described. Statements from citizens were given showing the 
destruction of trees and garden plants which had been accom- 
plished by the moth in Massachusetts during the years before 
the State began the work of extermination. 



THE INFESTED REGION REDUCED. 71 

It was shown in the report that the region occupied by 
the moth had been considerably reduced by the work already 
done, and the belief of the committee was stated that with the 
appropriation asked for still more could be accomplished 
toward reducing the infested area. The report described the 
probable condition of the parks, woodlands and farms of 
the State should the moth be allowed to go on unchecked. 
Every effort was made to place fully before the Legislat- 
ure the necessity of continuing the work with a view to 
extermination. 



72 THE GYPSY MOTH. 



The Work of 1894. 

Remembering the experience of former years, and con- 
sidering the likelihood of similar delay on the part of the 
Legislature and a consequent embarrassment of the work, 
the committee had laid their plans for 1893 so as to retain 
a considerable portion of that year's appropriation with which 
to begin the season of 1894. On Jan. 1, 1894, $29,744.69 
of that appropriation remained unexpended. This was re- 
tained in order that the most expert men of the force of 1893 
could be employed until such a time as the Legislature should 
make another appropriation. There were eighty-three men 
at work on January 1. 

Early in the year, Prof. N. S. Shaler, who had been a mem- 
ber of the committee from its organization in 1891 and who had 
been most active and prominent in the work, was obliged to 
resign from the Board of Agriculture on account of the press- 
ure of other duties. Since his resignation, however, he has 
kindly given his advice and assistance whenever called upon. 

On January 16, an order was presented to the Legislature 
by Representative Bullock of Fall River, which was after- 
wards adopted. This appears below, together with the 
answer made to it by the Board of Agriculture : — 

Ordered, That the State Board of Agriculture be instructed to 
report in writing to the General Court, on or before the first day 
of February next, the following facts aud estimates relative to the 
work of exterminating the gypsy moth : — 

1. The amount appropriated and amount expended annually 
for such purpose since the work began. 

2. The amount per year which, in the estimation of said Board, 
it will be necessary to expend upon such work during the next ten 
years. 

3. Whether, in the estimation of said Board, it will be neces- 
sary to continue the work of extermination for an indefinite period. 

4. If it will not be necessary to continue said work for an in- 
definite period, what is the probable limit of time during which it 
will be necessary to continue said work, and what will be the 
probable necessary expenditure therefor, in the aggregate, after 
the expiration of ten years from date. 



THE EXPENSE OF THE WORK. 73 

Reply by the Board. 

To the Senate and House of Representatives of the Commonwealth of 

Massachusetts. 

In response to an order of the Legislature under date of Jan. 
15, 1894, the State Board of Agriculture, by its gypsy moth com- 
mittee, presents the following " facts and estimates relative to the 
work of exterminating the gypsy moth." The amounts of appro- 
priations and expenditures have been reported in the several 
annual reports of the committee, and a summary of the same ap- 
pears in the report of the work of 1893, now in the hands of the 
Legislature. The original bills and pay-rolls, showing the details 
of all expenditures, may be found in the office of the State Auditor 
in the State House. 

The following is a condensed account of the appropriations made 
and the amounts expended annually : — 

Appropriations. 

March 14, 1890, $25,000 00 

June 3, 1890, 25,000 00 

June 3, 1891 50,000 00 

1892 75,000 00 

1893, 100,000 00 

Total appropriated, $275,000 00 



Expended in 1890 by First Commission. 

Salary of commissioners, $3,118 27 

Wages of employees, 15,278 32 

Other expenses, 7,142 73 



Total expended in 1890 $25,539 32 

Expended in 1891 by Second Commission. 
Balance of salaries due members of 

first commission, .... $630 95 

Salary of director, one and one-half 

months, 300 00 

Wages of employees, . . . .10,147 97 
Other expenses, including travelling 

expenses, teaming, rent, supplies and 

tools, 2,378 54 

$13,457 46 



Amounts carried forward, .... $13,457 46 $25,539 32 



74 THE GYPSY MOTH. 

Amounts brought forward, .... $13,457 46 $25,539 32 

Extended in 1891 by the State Board of 
Agriculture. 

Expenses of committee in charge of 
the work, $121 53 

Director's salary, seven and one-half 
months, 1,500 00 

Advising entomologist's salary and ex- 
penses, . . ... 280 84 

AVages of employees, .... 41,096 86 

Other expenses, including travelling 

expenses, teaming, rent, supplies and 

tools, 12,790 86 

55,790 09 

Total expended in 1891, .... 69,247 55 

Extended in 1892 by the State Board op Agriculture. 

Expenses of the committee in charge of the work, $130 49 

Director's salary, 2,400 00 

Advising entomologist's salary and expenses, . 525 60 

Wages of employees, 59,505 03 

Other expenses, including travelling expenses, 

teaming, rent, supplies and tools, . . . 11,979 84 

74,540 96 

Expended in 1893 by the State Board of Agriculture. 
Expenses of committee in charge of the work, 
Director's salary, ...... 

Advising entomologist's salary and expenses, 

Wages of employees, 

Other expenses, including travelling expenses 
teaming, rent, supplies and tools, 

Total expended to Jan. 1, 1894, 

The estimates called for must, from the nature of the attending 
circumstances, be only opinions. The plans for the work of 1893, 
for which an appropriation of 1165,000 was asked, contemplated 
a careful tree to tree search of all the forest land within the in- 
fested territory. This search would have cost a very large sum ; 
but as only sixty per cent, of the sum asked was appropriated, 
this, with much other work planned for the central district, was 
necessarily postponed. It was decided that the work of extermi- 
nation in the outer infested towns and the inspection of the terri- 
tory surrounding them still further out was most necessary and 
would contribute most toward extermination. Were the uncer- 



. $110 28 






. 2,400 


00 






730 


16 






. 59,039 


65 






. 13,647 


39 











75,927 


48 




. $245,255 31 



FUTURE EXPENSE ESTIMATED. 75 

taiuties which confront us in the condition of these forest lands 
eliminated, our opinions would more nearly approximate to the 
character of estimates made by experts when all the conditions of 
a problem are known. 

In 1893 considerable progress toward extermination was made. 
Ten towns were apparently cleared, comprising more than one-third 
of the territory originally infested. In 1894, with the appropriation 
asked for ($165,000), the committee ought to be able to bring 
into the same category Swampscott, Salem, Peabody, Wakefield, 
Woburn, Lexington, Winthrop and Franklin Park. This would 
leave Belmont, Arlington, Cambridge, Chelsea, East Boston, Ever- 
ett, Lynn, Maiden, Medford, Melrose, Revere, Saugus, Somerville, 
Stoneham and Winchester still infested. Several of these towns 
should be very nearly or quite cleared in 1894. But we have, in 
our estimates, left them with the list of probably uncleared. If, 
in 1895, $150,000 is appropriated, the work of that year should 
clear all towns but Arlington, Chelsea, Everett, Maiden, Medford, 
Melrose, Revere, Saugus and Somerville. The moth in these 
towns should then be brought to the verge of extermination so 
that, with an appropriation of $100,000, the work of 1896 would 
be quite likely to bring them very near to the condition of the 
cleared towns. During all this time a large amount of this money 
must be expended in closely inspecting the towns supposed to be 
cleared. In 1897 an appropriation of $50,000 would be necessary 
to provide for the completion of the work in the last-mentioned 
towns and for the necessary careful reinspection of the whole 
territory. We think this appropriation would also provide means 
to stamp out any possible remains of colonies supposed to be 
exterminated that might be found by the careful reinspection. 
For the five succeeding years we believe that an average annual 
appropriation of $25,000 would be necessary to continue the care- 
ful inspection of the whole territory and provide the means to deal 
with any colonies that may possibly have been overlooked. While 
it is our opinion that it is quite possible to exterminate the moth 
if large appropriations, such as have been mentioned, are granted 
for the next few years, we believe it also probable that should an 
appropriation of only $50,000 per year be granted the work would 
have to be continued indefinitely, as a very large proportion of 
such an appropriation would necessarily be expended in watching 
the outside territory and taking measures to prevent the spreading 
of the insect. 

Another method of estimating the pi'obable future cost of exter- 
mination would be to multiply the average cost of extermination 
per estate in the towns already cleared by the number of estates 



76 THE GYPSY MOTH. 

still infested. We estimate the number of estates still infested at 
eight thousand. Our records show that the average cost of exter- 
mination, per estate, in the towns cleared has been $41.10. At 
the same rate, the cost of exterminating the moth from eight 
thousand estates would be $328,800. This statement is made on 
the assumption that the estates yet infested are now in no worse 
condition than were those which had been cleared. This computa- 
tion does not include the large sum which must necessarily be 
expended in inspecting territory already cleared, that outside which 
must be watched, and the cost of reinspection for several years of 
these eight thousand estates after extermination is believed to 
have been accomplished. 

In the opinion of the committee the above-mentioned estimates 
afford the closest approximation to a forecast that can well be 
made. It is proper, however, to state that the questions asked 
by the Legislature cannot be answered with certainty. 
Respectfully submitted, 
Per order of the Gypsy Moth Committee 

of the State Board of Agriculture, 

Wm. P. Sessions, Chairman. 
Jan. 29, 1894. 

At the annual meeting of the Board of Agriculture on 
February 8, new by-laws were adopted, affecting a reorgan- 
ization of the Board. The committee in charge of the gypsy- 
moth work was thereafter known as the " committee on the 
gypsy moth, insects and birds," and its number was increased 
to six. 

The following is the article under which this committee 
acts : — 

It shall be charged with the duties of the gypsy moth committee, 
as provided for in chapter 210 of the Acts of 1891. All matters 
I'elating to birds and insects shall be referred to this committee, 
who shall report to the Board from time to time. 

The following; members of the Board were elected to serve 
upon this committee : E. W. Wood of Newton, Chairman, 
Wm. R. Sessions of Hampden, Francis H. Appleton of Pea- 
body, Wm. H. Bowker of Boston, F. W. Sargent of Ames- 
bury, and Augustus Pratt of North Middleborough. 



MR. APPLETON'S RESIGNATION. 77 

In the mean time the recommendation of the Board for an 
appropriation of $165,000 for the work of the year had been 
considered by the legislative committees. The joint stand- 
ing committee on agriculture had unanimously endorsed the 
recommendation and had reported a bill to the House provid- 
ing for an appropriation of $1G5,000. The committee on the 
gypsy moth, insects and birds, together with many citizens 
from the infested district, appeared before the committee on 
expenditures and urged that the full amount of the appro- 
priation be granted. But the latter committee, disregarding 
the recommendation of the committee on agriculture, reported 
a bill recommending an appropriation of $100,000. The 
committee on the gypsy moth, insects and birds also urged 
that a committee of the Legislature, consisting of three or 
five, be appointed to fully investigate the gypsy-moth work 
during the season and report to the next Legislature. This 
was not done. 

When it became known later that the Legislature had not 
approved the recommendation of the committee, and that only 
$100,000 had been appropriated, Mr. Francis H. Appleton, 
one of the original members of the committee, tendered to 
the Board of Agriculture his resignation as a member of the 
committee. The reasons given by Mr. Appleton were that 
inasmuch as the committee had plainly stated that a certain 
sum must be available in order to do all possible toward 
extermination in one year, and as the committee was required 
by law to use ' ' all possible and reasonable measures " to 
secure the extermination of the moth, and as with the $100,- 
000 the committee could do no more, in his opinion, than to 
continue the suppression of the moth, he felt it incumbent 
upon him to resign rather than to attempt a task which he 
believed impossible to accomplish with a less sum than had 
been recommended. 

As the committee had been elected by the Board and del- 
egated to this work, and as the Board would have no meeting 
during the spring or summer, the other members of the com- 
mittee considered it their duty to do all that was possible 
with the appropriation made, and report the result to the 
Board at its next annual meeting with such recommendations 
as should at that time seem best. 



78 THE GYPSY MOTH. 

On June 1 9 the executive committee of the State Board of 
Agriculture petitioned for an additional appropriation of 
$65,000, but the petition was referred by the Legislature 
to the next General Court. 

The work of destroying the eggs of the moth had been 
carried on, whenever the weather permitted, in January, 
February, March and April. During these months the Leg- 
islature had been considering the advisability of making the 
appropriation recommended by the committee in charge of 
the work. On March 6 the committee held a joint meeting 
with the Metropolitan Park Commission. Arrangements 
were made so that the work of the Board of Agriculture in 
the Middlesex Fells might not conflict with the plans of the 
Park Commission. The public forest reservation controlled 
by the Park Commission and situated in Maiden, Medford, 
Melrose, Stoneham and Winchester, includes most of the 
Middlesex Fells. 

On May 1, the appropriation of 1893 having been ex- 
pended, all field work was discontinued. Nothing was done 
in the field from that time until May 23, when the Legis- 
lature appropriated $100,000. More than three weeks of 
the best working time of the season were thus lost. Those 
portions of the infested region in which it had been planned 
to destroy the eggs or young caterpillars were left entirely 
unguarded and the caterpillars hatched and scattered over 
the surrounding country. Thus the delay of the appropria- 
tion made the work far more costly. Trained and experi- 
enced employees were obliged to seek positions elsewhere, 
and the indirect loss and delay occasioned were as detrimen- 
tal to the work as the loss of time when the men were laid 
off. " This enforced suspension of the work was most unfort- 
unate, occurring as it did when the men were destroying 
the egg-clusters at the rate of thousands per day. Before 
work was resumed the remaining eggs had hatched and the 
larvae had scattered. Had the work not been thus inter- 
rupted, it would have been possible in many places to 
destroy these young larvae en masse by means of burning."* 



* Fourth Report .of the Board of Agriculture on the work of Extermination of the 
Gypsy Moth, January, 1S95. 



VISITS OF ENTOMOLOGISTS. 79 

As soon as possible after the appropriation was available 
all those experienced and trustworthy men who could be 
reached were re-employed. The trees were burlapped and 
all haste made to prepare the infested trees for the summer 
work. In many places the caterpillars appeared in large 
numbers and it required the work of the entire season to 
hold them in check. 

The hatching and scattering of the caterpillars, which the 
delay of the appropriation allowed, necessitated the burlap- 
ping of a greater number of trees and the employment of a 
larger force for the summer. There were 624,673 trees bur- 
lapped during the summer and 265 men were of necessity em- 
ployed to attend the burlaps. The result was the destruction 
at a great expense of a great number of caterpillars, many of 
which would not have existed had the appropriation been made 
at an earlier date. A large part of the appropriation having 
been used in burlapping trees and killing caterpillars during 
the summer, it became necessary to discharge a large part 
of the force at the end of the burlapping season on August 
25. Thirty-three men were then discharged and others 
were discharged in September, so that by October 1 only 
133 men remained. This force was entirely insufficient to 
inspect thoroughly the 220 square miles in the known infested 
region, to say nothing of the belt of territory outside of it 
which the committee believed ought to be inspected. The 
men were kept at work during every day when it was possi- 
ble to work to advantage, and everything was done that 
could be done with the small force remaining to inspect the 
outer towns of the infested region. It was found necessary 
again to neglect the central towns to a certain extent that 
the outer towns might be inspected as thoroughly as possible 
and that the moth's spreading might be prevented. 

In June Dr. George H. Perkins of the University of Ver- 
mont, entomologist of the Vermont State Agricultural Ex- 
periment Station, visited the infested region upon invitation 
of the committee and inspected the work. In July Prof. F. 
L. Harvey, botanist and entomologist of the Experiment 
Station at the Maine State College, Prof. J. Henry Comstock 
of Cornell University, formerly United States entomologist, 
and Mr. L. O. Howard, entomologist of the United States 



80 THE GYPSY MOTH. 

Department of Agriculture, examined the infested region 
and inspected the work. These gentlemen gave the com- 
mittee the benefit of their criticism and advice in the field, 
and Professors Perkins, Harvey and Comstock made written 
reports to the committee. (See Appendix E.) 

Mr. Howard, later, in his annual address before the sixth 
annual meeting of the Association of Economic Entomolo- 
gists, of which he was president, gave his impressions and 
opinions of the work. (See Appendix E.) 

During the summer the experiment in trapping male 
moths was tried on a larger scale than in 1893. While mauy 
moths were destroyed, the results as a whole were not suc- 
cessful enough to warrant the adoption of the method in 
field work. Arsenate of lead (first experimented with in 
1893) was used in spraying to a limited extent during the 
spring. While more effective than Paris green, it was 
determined that it could not be depended upon to exter- 
minate. 

The fall inspection in Boston revealed the presence of 
moths in three sections of the city not before known to be 
infested — Roxbury, Dorchester and the city proper. One 
colony was found in each section. Two of them had been 
established evidently for several years, but the demands of 
the work elsewhere had hitherto prevented an inspection of 
this large territory. 

The inspection of towns which had been apparently cleared 
in 1893 revealed a few egg-clusters or other forms of the 
moth in all of them. A careful search of a portion of the 
unexplored wooded region revealed a number of small col' 
onies in the Lynn field woods. With this exception very 
few moths were found in any of these towns. The discovery 
of the moths in these towns emphasized the necessity of 
keeping them under surveillance for a few years after they 
had been apparently cleared and as long as there were moths 
in any of the adjacent towns. 

The discovery of the moths in the Lynnfield woods verified 
the prediction which the committee made in 1893, of the 
probability of the moth's existence in the wooded region, and 
showed the necessity of a sufficient appropriation to thor- 
oughly search the woodland. The committee in its report 



CONDITION OF THE REGION. 81 

to the Legislature stated the condition of the infested region 
as follows : — 

In ten of the outer towns the moth has been apparently extermi- 
nated ; in five more it has been very nearly exterminated. More 
than a thousand well-marked moth colonies have been stamped 
out of existence. In all of the infested towns such sections as 
have been worked over year after year by the employees of the 
State Board of Agriculture are now nearly cleared of the moth, 
and the general condition of the inhabited and cultivated lands 
is better than ever before. Against this favorable condition of 
such portions of these towns we must place the fact which has 
been revealed by the inspection of the past season, — that the 
woodlands in many of the towns are much more generally infested 
than has been hitherto supposed. Scattered colonies of the moth 
are known in the woods of Lexington, Winchester, Arlington, 
Belmont, Stoneham, Medford, Wakefield, Melrose, Maiden, Lynn- 
field, Saugus, Revere, Swampscott, Lynn and Salem. 

This condition of the forested lands is due to the fact that there 
has not been money enough to provide for destruction of these 
colonies whenever found. It has been impossible, with the means 
at our command, to make a thorough search of all this woodland ; 
but during the past season special efforts have been made to in- 
spect it so far as was possible under the circumstances, and enough 
is now known to justify the presumption that colonies of the moth 
are scattered through the woods from Lexington to the sea. Though 
many of the colonies found have apparently had their origin within 
two or three years, many others originated at least ten years since. 
The woodland which is thus more or less infested probably covers 
fifty square miles of the central and north-central portions of the 
infested district. 

In the attempt to exterminate the gypsy moth it was early 
ascertained that the species was spread over a region many times 
greater than that which was at first known to be infested, and that 
it was not confined to lands under cultivation, but had penetrated 
to some extent into the woodlands. These discoveries made it 
certain that extermination would be extremely difficult, requiring 
years for accomplishment even under the most favorable condi- 
tions. The best methods known and used at first were not effect- 
ual in securing extermination, and the methods which later proved 
effective were so expensive that they could not be carried out over 
so large an area without larger appropriations than those which 
have been granted. 

Although the extent of the infested region, the existence of the 



82 THE GYPSY MOTH. 

moths in the woods and the great expense of exterminative 
methods have been all repeatedly presented to the Legislature in 
the annual reports of this Board, the amount appropriated for 
each of the past two years has been only about two-thirds of that 
recommended by the Board as absolutely necessary to do all that 
could be done to advantage under the circumstances. 

The law requires the Board " to use all reasonable measures to 
prevent the spreading and to secure the extermination " of the 
moth. The Board has apparently been successful in preventing 
the spread of the moth and has considerably lessened the area 
known to be infested. It has never had an appropriation sulli- 
ciently large to do all that might have been done in one year toward 
the extermination of the moth. If the work is to be carried on 
under the present statute, and the policy of extermination is to be 
continued, we believe that two hundred thousand dollars should be 
appropriated for the work of the coming year. 

The committee believes that the work of extermination should 
be continued, but is also firmly of the opinion that, if the Legis- 
lature is unwilling to appropriate the sum necessary for an aggres- 
sive campaign for extermination, the law should be changed so 
that the Board of Agriculture shall be required to conduct the 
work only along the line of preventing the spread of the gypsy 
moth. The committee further believes that, if the Legislature is 
unwilling to provide sufficient funds for restricting the spread of 
the gypsy moth and holding it in check, the work should be dis- 
continued entirely. The committee is not in favor of appropri- 
ating inadequate funds for the work in hand. It seems unjust 
to require the extermination of the pest while providing inadequate 
means for the purpose. The Board of Agriculture has recom- 
mended for each of the past two years an appropriation of one 
hundred and sixty-five thousand dollars, believing that sum was 
absolutely required for the successful prosecution of the work. 
The Legislature has appropriated only one hundred thousand 
dollars, or about sixty per cent, of the sum asked for each of 
these years.* 



* Fourth Report of the State Board of Agriculture on the work of Extermination 
of the Gypsy Moth, January, 1895. 




PLATE XIII. Oak and pine woods attacked by the gypsy moth. From a 
photograph taken in Lexington, July 11, 1895. 



THE WORK OF 1895. 83 



The Work of 1895. 

The Legislature of 1894 had adopted a resolve request- 
ing the senators and representatives from Massachusetts in 
the Congress of the United States to urge upon Congress the 
necessity of prompt and vigorous action to exterminate the 
gypsy moth, and to use their influence to secure from Con- 
gress an appropriation of one hundred thousand dollars to 
assist this Commonwealth in defraying the necessary ex- 
penses of the work. 

The Board of Agriculture was notified by the agricultural 
committee of the United States Senate that a hearing would 
be given on Friday, Jan. 4, 1895, upon the resolve presented 
by the Massachusetts Legislature. A committee consisting 
of Francis H. Appleton, vice-president, and Wm. R. Ses- 
sions, secretary, of the Board of Agriculture, accompanied 
by the director of field work, appeared on January 5 before 
the Senate committee on agriculture, and also before the 
committee on agriculture of the United States House of 
Representatives, at a special hearing upon a resolution in- 
troduced into Congress by Hon. William Cogswell, which 
provided for the appropriation asked for by the resolution 
of the Massachusetts Legislature. The committee also pre- 
sented the matter to Hon. J. Sterling Morton, secretary of 
the United States Department of Agriculture. Later, a re- 
solve appropriating forty thousand dollars for the extermina- 
tion of the gypsy moth passed the United States Senate but 
was defeated in a conference committee chosen from both 
houses. 

At the annual meeting of the Board of Agriculture, Feb. 
6, 1895, Mr. Wm. H. Bowker, a member of the committee 
on the gypsy moth, insects and birds, retired from the Board, 
his term having expired on that day. Mr. Bowker had been 
a prominent member of the Board, and its reorganization 
was the outcome of his suggestions. The two vacancies in 
the membership of the committee, left by the resignation in 
1894 of Mr, Appleton and the retirement of Mr. Bowker, 



84 THE GYPSY MOTH. 

were filled by the election of Messrs. John G. Avery of 
Spencer and S. S. Stetson of Lakeville. 

The report of the Board of Agriculture, containing a recom- 
mendation for an appropriation of two hundred thousand dol- 
lars, was presented to the legislative committee on agriculture 
immediately after its organization in January. Some oppo- 
sition to the appropriation developed in the committee, and 
the time and attention of the members were occupied for 
some weeks with other important measures. This committee 
held public hearings during the week beginning February 11, 
at which hundreds of citizens from the infested towns were 
present. The preponderance of sentiment was in favor of 
granting the appropriation asked for. On March 21 the 
committee finally acted upon the matter, and reported a 
resolve calling for an appropriation of one hundred and fifty 
thousand dollars. Although this amount was looked upon 
by the Board of Agriculture as entirely inadequate, there 
appeared to be fully as much danger to the work by delay in 
making the appropriation as by reduction of its size. The 
committee on the gypsy moth, insects and birds therefore 
endeavored to urge upon the General Court the immediate 
passage of the bill as reported by the committee on agri- 
culture. But it was not until May 17 that the appropriation 
of one hundred and fifty thousand dollars finally became avail- 
able. Early in the year the appropriation of 1894 was nearly 
exhausted and on February 6 the field force was discharged. 
The work of destroying the eggs of the moth, which should 
have been carried on during the spring in those portions of 
the infested towns not wholly cleared of them in the fall, was 
thereby brought to an end. Thus the experience of 1894 was 
repeated, but the amount of working time (three months) lost 
in 1895, owing to the lateness of the appropriation, was much 
greater than in the previous year. The discontinuance of the 
field work in 1895 was especially disastrous because occurring 
in an early spring which later developments showed was par- 
ticularly favorable for the moths' increase. The great mul- 
tiplication of the numbers of the moth which occurred during 
this favorable season, their scattering abroad and the con- 
sequent injury to trees by their feeding, might have been 
prevented by destroying the eggs in the spring. 




PLATE XIV. Oak trees stripped by caterpillars of the gypsy moth, Sar- 
gent Street, Dorchester. (Ward 16, Boston.) From a 
photograph taken July 24, 1895. 



DELAY IN LEGISLATION. 85 

When it became evident that there would be considerable 
delay in legislation, the committee authorized the director to 
employ as a nucleus of an organization such experienced men 
as were willing to wait for their pay until such time as the 
Legislature should make an appropriation: The office force 
was employed ; the records were closed up ; examinations of 
applicants for positions on the force were begun ; arrange- 
ments were made for the purchase of supplies ; and other 
preliminaries, providing for the early employment of a full 
force of men, were arranged. When the appropriation 
became available, it was too late in the season to accom- 
plish much by the destruction of eggs, for most of them had 
hatched. As the men were nit at work, those who were 
inexperienced were given a week or more of training in 
clearing up infested woodlands and cutting and burning 
brush. They were then organized into burlapping gangs 
and employed in placing burlap bands around the trees in 
infested localities. 

It was found necessary to increase the force as rapidly as 
the careful selection and examination of men allowed, for the 
caterpillars of the moth were appearing numerously wherever 
the egg-clusters had not been destroyed. As the season 
advanced the great increase in the numbers of the moth was 
noticeable. More men than were ever before employed in 
the work were engaged to meet the emergency. On July 
20 three hundred and fifty men were at work, and even with 
this force it was not possible to prevent occasional injury to 
foliage in certain places. A swarm of caterpillars appeared 
in one locality in Dorchester, within a few rods of the point 
where the inspection of the winter previous had ceased on 
account of snow. Many of the trees in an oak grove were 
defoliated before the presence of the caterpillars was dis- 
covered. Immediate steps were taken to destroy them and 
in a short time some eighteen bushels of caterpillars were 
killed in this locality. 

Various points in the woods of Lexington and Woburn 
were found to be swarming with the caterpillars of the gypsy 
moth. Here they defoliated several acres of woodland. 
Later in the season similar colonies were discovered in the 
woods of Medford, one being situated in the southern por- 



86 THE GYPSY MOTH. 

tion of the metropolitan park reservation known as the 
Middlesex Fells. Others were found in the Saugus woods. 
In some of the localities where the moth appeared in num- 
bers in the woods the injury extended over from one to 
three acres, leaving the trees as bare as in winter. 

Wherever the forest was defoliated in this manner the 
infested trees presented from a distance the appearance of 
having been killed by fire. These reddish patches on the 
hillsides stood out strongly in contrast with the green of the 
summer foliage by which they were surrounded. On enter- 
ing one of these infested spots during the time when the 
caterpillars were feeding, one was immediately struck by the 
rustling sound caused by their movements and the falling of 
their droppings and the bits of foliage which they were con- 
tinually cutting from the leaves. A little later in the season, 
during the warmer part of the day, the male moths fluttered 
in swarms about the trees while the white females were scat- 
tered over the trunks and branches of trees and upon the dry 
leaves on the ground. 

Nearly all species of trees and most herbaceous plants in 
this badly infested woodland were stripped by the caterpil- 
lars. In some places they ate the foliage of the pines, both 
young and old. Some of these trees appear now to be dy- 
ing. But on account of the unusually rapid development of 
the moths this season, their consequent maturing and ces- 
sation of feeding, the trees were not continually stripped 
throughout the summer ; therefore the deciduous trees began 
to throw out new foliage late in July and early in August, 
when the female moths were laying their eggs. This rapid 
development of the moths during the past season appears to 
be unprecedented in this country so far as can be ascertained. 
As the probable result, a second brood of the moths appeared 
in one locality in Woburn. Young caterpillars were found 
leaving the egg-clusters in the first weeks of September. 
As the summer waned, many localities in the woods were 
found where the egg-clusters of the moth were quite numer- 
ous, bidding fair, if not destroyed, to produce a brood of 
caterpillars during 1896 which may prove even more de- 
structive than those of the present season. 

This condition of affairs fulfilled the predictions which the 



Wgtgf000^t/9flt0Kf^i0tti 





PLATE XV. Woodland colony of the gypsy moth as seen at a distance of 
one-third of a mile. The light area in the woods in the background 
shows the appearance of a defoliated tract as compared with 
the surrounding uninfested trees. From a photo- 
graph taken in Woburn, July 19, 1895. 



THE WOODS INFESTED. 87 

committee made to the Legislature in former years, namely, 
that the moths were distributed generally through the wood- 
land in the inner towns of the infested region, and demon- 
strated that they might prove a serious danger to wooded 
parks and forests. Experts were sent into the woods to 
examine them as thoroughly as was possible during the 
summer. They discovered that a large portion of the Mid- 
dlesex Fells was more or less infested by the moth. At 
least one thousand acres of this reservation now appear to 
be in this condition. In Saugus a tract of about the same 
size appears to be similarly affected, and another even larger, 
situated in Woburn, Lexington and Arlington, is also more 
or less infested. There are at least three thousand acres of 
woodland in the foregoing towns that are now known to be 
infested by the gypsy moth. This condition had been sus- 
pected, but the appropriation had never been sufficient to 
watch the cultivated lands and highways and also to care 
for the forested region. 

Throughout the season of 1895, as in previous seasons, 
experiments on insecticides were conducted in the field and 
observations were made on the habits of the moth and its 
enemies. A small building was erected in the Maiden 
woods for use as an experiment station, and to facilitate the 
breeding of parasites and predaceous insects to be used for 
experimental purposes. In all probability the results ob- 
tained from observations and experiments in 1895 are more 
valuable than those of former years. The experiments and 
their results are treated of in the report of the entomologist. 

In some localities, where the moths were numerous upon 
valuable ornamental shrubs or trees, the foliage was sprayed 
with arsenate of lead. Where it was used at a strength of 
thirty pounds to one hundred and fifty gallons of water all 
the caterpillars appeared to be destroyed. 

During the season fire was used with good effect in many 
cases to check the ravages of the caterpillars in waste land. 

At the time of going to press little can be said of the 
results of the work of 1895. It may be predicted, however, 
that considering the phenomenal increase of the moths in 
those sections where egg killing was not done in the spring 
because of the delay of the appropriation, and considering 



88 THE GYPSY MOTH. 

also the large number of men employed later, the results 
of the season's work will show a greater number of the dif- 
ferent forms of the moth destroyed than at any time since 
1891. 

We have long feared that unless appropriations suffi- 
cient for complete eradication were granted, some favorable 
season might give the moths a sudden impetus which would 
cause them to increase beyond immediate control. Such an 
emergency has arisen, and in the centres of population, in 
cultivated lands and along the highways, it has been fully met. 
It is true that in the woodland where the greatest infestation 
occurred some injury was done for a time by the moths, but, 
in such places, they are now under control, and with vigor- 
ous measures they may be entirely exterminated from these 
localities within two or three years. Yet there is a large 
wooded region in the north-central towns which never has 
been thoroughly cared for and never can be unless larger 
appropriations are made. In many portions of this wood- 
land the moths are doubtless steadily increasing in numbers, 
and all that has been done or can be done there, with the 
means thus far furnished by the Commonwealth, is to check 
them whenever they appear in such numbers as to threaten 
serious injury to the trees. 

The results of the work of 1895 will be presented in the 
next annual report to the Legislature. 



NUMBER OF EMPLOYEES. 



89 



The Number of Men employed and Work 
done, 1890 to 1894 Inclusive. 

In order to give an opportunity for comparing the number 
of employees and the amount of work done each year we 
give tables taken from the pay-rolls of 1890 and the reports 
of the years 1891 to 1894 inclusive : — 

1890. 





Number of 




Number of 




Men. 




Men. 


Mar. 24-29, . 


27 


Aug. 4- 9, . 


7 


" 31-April 5, 




57 


" 11-16, . 






- 


April 7-12, . 




74 


" 18-23, . 






- 


" 14-19, . 




62 


" 25-30, . 






- 


" 21-26, . 




59 


Sept. 1-6, . 






- 


" 28-May 3, 




51 


" 8-13, . 






2 


May 5-10, . 




53 


" 15-20, . 






2 


" 12-17, . 




36 


" 22-27, . 






4 


" 19-24, . 




65 


" 29-0ct. 4, 






5 


" 26-31, . 




72 


Oct. 6-11, . 






7 


June 2- 7, . 




76 


" 13-18, . 






5 


9-14, . 




88 


" 20-25, . 






18 


" 16-21, . 




89 


" 27-Nov. 1, 






40 


" 23-28, . 




89 


Nov. 3- 8, . 






25 


" 30-July 5, 




84 


" 10-15, . 






28 


July 7-12, . 




79 


" 17-22, . 






28 


" 14-19, . 




80 


" 24-29, . 






30 


" 21-26, . 




42 


Dec. 1- 6, . 






29 


" 28-Aug. 2, 




9 







1891. 



Mar. 20, 21, . 


16 


June 22-27, . 


217 


" 23-28, . 




40 


" 29-July 4, 




209 


" 30-April 4, 




103 


July 6-11, . 




192 


April 5-11, . 




129 


" 13-18, . 




170 


" 13-18, . 




140 


" 20-25, . 




104 


" 20-25, . 




146 


" 27-Aug. 1, 




106 


" 26-May 2, 




167 


Aug. 3- 8, . 




99 


May 4- 9, . 




173 


" 10-15, . 




98 


" 11-16, . 




199 


" 17-22, . 




96 


" 18-23, . 




195 


" 24-29, . 




88 


" 25-30, . 




211 


" 31-Sept. 5, 




83 


June 1- 6, . 




238 


Sept. 7-12, . 




75 


8-13, . 




242 


" 14-19, . 




73 


" 14-20, . 




211 


" 21-26, . 




67 



90 



THE GYPSY MOTH 



1 8 9 1 — Concluded. 





Number of 




Number of 




Men. 




Men. 


Sept. 28-Oct. 3, 


62 


Nov. 16-21, . 


45 


Oct. 5-10, . 


58 


" 23-28, . 






43 


" 12-17, . 


58 


" 30-Dec. 5, 






41 


" 19-24, . 


61 


Dec. 7-12, . 






41 


" 26-31, . 


59 


" 14-19, . 






42 


Nov. 2- 7, . 


44 


" 21-26, . 






42 


" 9-14, . 


44 


" 28-Jan. 2, 






42 







1892. 






Jan. 4- 9, . 


46 


July 


4- 9, . . . 


95 


" 11-16, . 




46 




11-16, . 


102 


" 18-23, . 




47 


U 


18-23, . 


120 


" 25-30, . 




48 


u 


25-30, . 


120 


Feb. 1- 6, . 




48 


Aug. 


1- 6, . 


126 


8-13, . 




48 


U 


8-13, . 


129 


" 15-20, . 




31 


it 


15-20, . 


122 


" 22-27, . 




68 


" 


22-27, . 


107 


" 29-Mar. 5, 




88 


" 


29-Sept. 3, . 


107 


Mar. 7-12, . 




111 


Sept. 


5-10, . 


97 


" 14-19, . 




127 


" 


12-17, . 


95 


" 21-26, . 




141 


(S 


19-24, . 


37 


" 28-April 2, 




191 


tC 


26-30, . 


33 


April 4- 9, . 




219 


Oct. 


3- 8, . 


38 


" 11-16, . 




234 


a 


10-15, . 


36 


" 18-23, . 




233 


" 


17-22, . 


37 


" 25-30, . 




230 


" 


24-29, . 


37 


May 2- 7, . 




232 


« 


31-Nov. 5, . 


38 


9-14, . 




183 


Nov. 


7-12, . 


38 


" 16-21, . 




140 


(s 


14-19, . 


37 


" 23-28, . 




140 


" 


21-26, . 


34 


" 30-June 4, 




91 


tt 


28-Dec. 3, . 


36 


June 6-11, 




90 


Dec. 


5-10, . 


36 


" 13-18, . 




87 


it 


12-17, . 


35 


" 20-25, . 




89 


It 


19-24, . 


34 


" 27-July 2, 




93 


u 


26-31, . 


33 



1893. 



Jan. 2- 7, . 


30 


Mar. 20-25, . 


8 


9-14, . 






28 


" 27-April 1, 




27 


" 16-21, . 






28 


April 3- 8, . 




44 


" 23-28, . 






27 


" 10-15, 






93 


" 29-Feb. 4, 






25 


" 17-22, 






115 


Feb. 6-11, . 






24 


" 24-29, 






125 


" 13-18, . 






24 


May 1- 6, 






128 


" 20-25, . 






22 


8-13, 






132 


" 27-Mar. 4, 






25 


" 15-20, 






132 


Mar. 6-11, . 






25 


" 22-27, 






132 


" 13-18, . 






— 


" 29-June 3, 




131 



NUMBER OF EMPLOYEES. 



91 







1893 — 


Concluded. 








Number of 




Number of 




Men. 




Men. 


June 5-10, . 


128 


Sept. 18-23, . 


93 


" 12-17, . 




131 


" 25-30, . 




89 


" 19-24, . 




132 


Oct. 2- 7, . 




86 


" 26-July 1, 




149 


9-14, . 




85 


July 3- 8, . 




153 


" 16-21, . 




89 


" 10-15, . 




154 


" 23-28, . 




88 


" 17-22, . 




147 


" 30-Nov. 4, 




88 


" 24-29, . 




151 


Nov. 6-11, . 




88 


" 3l-Aug. 5, 




146 


" 13-18, . 




88 


Aug. 7-12, . 




144 


" 20-25, . 




85 


" 14-19, . 




126 


" 27-Dec. 2, 




85 


" 21-26, . 




125 


Dec. 4- 9, . 




85 


" 28-Sept. 2, 




121 


" 11-16, . 




86 


Sept. 4- 9, . 




101 


" 18-23, . 




85 


" 11-16, . 




95 

1 


" 25-30, . 




83 







1894. 






Jan. 1- 6, 


82 


June 25-30, . 


261 


8-13, . 




86 


July 2- 7, . 




265 


" 15-20, . 




85 


9-14, . 




270 


" 22-27, . 




86 


" 16-21, . 




265 


" 29-Feb. 3, 




83 


" 23-28, . 




270 


Feb. 5-10, . 




82 


" 30-Aug. 4, 




261 


" 12-13, . 




82 


Aug. 6-11, . 




266 


" 14-17, . 




23 


" 13-18, . 




260 


" 19-24, . 




81 


" 20-25, . 




216 


" 26-Mar. 3, 




81 


" 27-Sept. 1, 




15 


Mar. 5-10, . 




82 


Sept. 3- 8, . 




16 


" 12-17, . 




84 


" 10-15, . 




147 


" 19-24, . 




85 


" 17-22, . 




148 


" 26-31, . 




91 


" 24-29, . 




133 


April 2- 7, . 




95- 


Oct. 1- 6, . 




133 


9-14, . 




121 


" 8-13, . 




131 


" 16-21, . 




157 


" 15-20, . 




123 


" 23-28, . 




159 


" 22-27, . 




125 


" 30-May 1, 




156 


" 29-Nov. 3, 




128 


May 2- 9, . 




15 


Nov. 5-10, . 




128 


" 10-12, . 




164 


" 12-17, . 




133 


" 14-19, . 




173 


" 19-24, . 




133 


" 21-26, . 




213 


" 26-Dec. 1, 




132 


" 28-June 2, 




228 


Dec. 3- 8, . 




132 


June 4-9, 




230 


" 10-15, . 




134 


" 11-16, . 




229 


" 17-22, . 




135 


" 18-23, . 




225 


" 24-29, . 




132 



Summary of Work done during Four Years. 

During the year 1890 no account of the number of dif- 
ferent forms of the moth destroyed was kept by the first 



92 



THE GYPSY MOTH. 



commission, and the reports of the work are not in a form 
that can be used in making tables of the kind given below. 
It would have been almost impossible to keep any accurate 
account of the immense numbers of the moth destroyed 
during 1890. This was also true of the first few months of 
1891. Therefore no figures or estimates of the numbers 
killed during those years are given in the tables. The 
egg-clusters destroyed during the first weeks of 1891 were 
estimated at eight cart-loads. During the latter part of 
that year a systematic account was kept of the number of the 
different forms of the moth found on each infested estate, and 
from that and the other accounts of the season, a somewhat 
incomplete table of the work of 1891 has been made. A 
fuller account is given of the work of the succeeding years. 
Yet even this summary cannot be considered as complete, 
for the tables pertain mainly to the hand work done annually, 
and only such figures are given as from their nature can be 
accurately recorded. Obviously no account could be kept 
of the number of moths destroyed by spraying, fire and other 
wholesale measures. 

It will be seen that though a larger number of men was 
employed in 1893 and 1894 than in 1892, fewer trees were 
found infested in the later years, although the number of 
the different forms of the moth killed by hand was larger. 
This may be chiefly accounted for by the extension of the 
work into woodlands in the inner towns, where the moths 
had increased unmolested. In badly infested places in the 
woods the number of moths per tree was very great. Many 
caterpillars, pupae and egg-clusters were destroyed in bushes 
and young growth. This greatly swelled the sum total of 
forms of the moth destroyed. The larger appropriation of 
1894 made this woodland work possible. 



Trees (fruit, shade and forest) : — 

Inspected, 

Found to be infested with caterpillars, 
pupa;, moths or eggs, . 

Cleared of eggs 

Cemented, 

Banded (insect lime or tree ink), • 



3,591,982 

213,828 

212,432 

19,296 

12,000 



2,109,852 

108,428 
99,989 
12,172 
21,251 



4,108,494 

44,716 
2,068 
4,583 

19,453 



6,828,229 

48,752 
2,176 
7,844 



SUMMARY OF WORK. 



93 



1893. 



Trees (fruit, shade and forest) — Con. 

Burlapped, 

Sprayed, 

Trimmed, 

Scraped, 

Cut, 

Acres of brush land and woodland cut 
and burned over 

Buildings: — 

Inspected, 

Found to be infested, .... 
Cleared of eggs 

Wooden fences: — 

Inspected, 

Found to be infested, .... 
Cleared of eggs, 

Stone walls : — 

Inspected, 

Found to be infested, .... 
Cleared of eggs, 

Number of each form of the moth destroyed 
by hand . — 

Caterpillars, 

Pupas, 

Moths 

Hatched or infertile egg-clusters, 
Unhatcbed and probably fertile egg- 
clusters, 



68,720 
177,415 



120 



87,536 
3,647 
3,574 



53,219 
6,808 
6,570 



110,108 
7,372 

395 

115 



22,102 
1,557 
1,427 



24,936 
2,365 
2,159 



2,213 
672 
354 



935,656 

80,021 

9,338 

40,954 

99,790 



419,434 
5,145 
1,906 
2,406 
4,055 

184 



8,828 
348 
232 



15,092 
713 
541 



814 

225 

93 



1,173,351 

77,029 

5,655 

6,868 

46,101 



624,673 

14,857 
8,618 
6,068 

10,296 

3364, 



27,430 

508 

55 



35,276 

798 

99 



1,620 

423 

44 



1,153,560 
92,225 
18,084 
18,036 

94,706 



94 THE GYPSY MOTH. 



The Increase and Distribution of 
the Gypsy Moth. 

The Rate of Increase. 

The study of the increase and dissemination of the gypsy 
moth in Massachusetts is most interesting. Perhaps there 
never has been a case where the origin and advance of an 
insect invasion could be more readily traced. As the moth 
appears to be confined as yet to a comparatively small area, 
and as the region has been examined more or less thoroughly 
for five successive years, the opportunities offered for the 
study of the multiplication and distribution of the insect 
have been unequalled. 

When it is considered that the number of eggs deposited 
by the female averages from 450 to 600, that 1,000 cater- 
pillars have been seen to hatch from a single egg-cluster, 
and that at least one egg-cluster has been found containing 
over 1,400 eggs, there can be no doubt that the reproductive 
powers of the moth are enormous. Mr. A. H. Kirkland has 
made calculations which show that in eight years the unre- 
stricted increase of a single pair of gypsy moths would be 
sufficient to devour all vegetation in the United States. This, 
of course, could never occur in nature, and is mentioned 
here merely to give an idea of the reproductive capacity of 
the insect. 

It seems remarkable at first sight that an insect of such 
reproductive powers, which had been in existence in the State 
for twenty years, unrestrained by any organized effort on the 
part of man, did not spread over a greater territory than 
thirty townships, or about two hundred and twenty square 
miles. Some of the causes which at first checked its increase 
and limited its diffusion in Medford have already been set 
forth (pages 5-7 ) . Most of the checks which at first served 
to prevent the excessive multiplication of the gypsy moth in 
Medford operate effectively to-day wherever the species is iso- 
lated. True, it has now become acclimated. But any small 
isolated moth colony still suffers greatly from the attacks 



ITS RATE OF INCREASE. 95 

of its natural enemies and from the struggle with other 
adverse influences which encompass it. The normal rate of 
increase in such isolated colonies as are found to-day in 
the outer towns of the infested district is seen to be small. 
The annual increase can be readily ascertained by noting 
the relative number of egg-clusters laid in successive years, 
the unhatched or latest clusters being easily distinguished 
from the hatched or "old" clusters, and the age of these 
latter, whether one, two, three or more years, being indi- 
cated by their state of preservation. The ratio of the aver- 
age annual increase of ten such colonies was found to be 
6.42, — that is, six or seven egg-clusters on an average may 
be found in the second season to one of the first season. 

Though even at this rate of increase the progeny of a 
single pair of moths would be numerically enormous within 
twenty years,* yet for the first few years, under normal con- 
ditions, the increase of a small and isolated moth colony is 
not great enough to work any serious or extended injury. 
The great army of moths does not advance rapidly by the 
skirmish line, as it were, but only by the main body, for a 
great increase and rapid spread to a distance can only occur 
where the moths have become so numerous over a consider- 
able area as to have nearly reached the limit of their food 
supply. 

Conditions favoring Rapid Increase. 
When any colony under average normal conditions has 
grown to a considerable size and then receives an added 
impetus from exceptionally favorable conditions, its power 
of multiplication and its expansive energy are greatly aug- 
mented and its annual increase rises above all calculations.! 
Under such influences hundreds of egg-clusters will appear 
in the fall where few were to be seen in the spring, and 
thousands are found where scores only were known before. 
It is probable that the season of 1889 was particularly favor- 



* At this ratio the number of egg-clusters produced in the twentieth year would be 
14,148,179,507,899,404. 

t The increase of these large colonies seems to be limited only by the supply of food. 
Whenever food becomes scarce many of the moths are less prolific. The larvae which 
do not find sufficient food either die or develop early, and the female moths lay fewer 
eggs than those which transform from well-nourished caterpillars. 



96 THE GYPSY MOTH. 

able for the moths' increase. The season of 1894 and that 
of 1895 appear also to have furnished conditions especially 
favorable for an abnormal multiplication of the insect. 

The operation of the causes of these sudden outbreaks 
is not fully understood. It is evident, however, that the 
warm, pleasant spring weather of the past two years (1894 
and 1895) hastened the development of the caterpillars, 
thereby shortening their term of life. The length of life of 
the caterpillar varies from six to twelve weeks. During cold, 
rainy weather the caterpillars eat little and grow slowly. 
During warm, dry weather they consume much more food 
and grow with great rapidity. In the unusually warm 
spring and early summer of 1895 many of the caterpillars 
moulted a less number of times than usual, and their length 
of life did not exceed six or seven weeks. Under these 
conditions they proved more quickly injurious to foliage 
than in a more normal season, and were more completely 
destructive within any given area in which their numbers 
were great. And they were not so long exposed to the 
attacks of their enemies. While it may be true that the 
parasitic enemies of the moth will also develop rapidly 
under conditions that hasten the growth of their host, birds 
and other vertebrate enemies will secure fewer of the moths 
in six or seven weeks than in ten or twelve. This would 
probably be true of many predaceous insects. It is believed 
that dry weather is unfavorable for vegetable parasites of 
insects, but to what extent the caterpillars are affected by 
them in a humid season it is impossible to say. 

The past two years have been ' ' canker worm years " in 
the infested region. Many of the birds which habitually 
feed on the caterpillars of the gypsy moth have been largely 
occupied during May and the early part of June in catch- 
ing canker worms, which they seem to prefer, turning their 
attention to the gypsy-moth caterpillars in the latter part 
of June and July, when the canker worms have disappeared. 
The birds, therefore, have not been as useful in checking the 
increase of the gypsy moth as in years when the canker worms 
were less numerous. 

A few of the restraining influences which have been less 
active than usual during the past two years have been men- 




t< CO 



™ o» 



<D © 



CONDITIONS FAVORING INCREASE. 97 

tioned, and possibly many others have escaped observation, 
but those given may serve in a measure to explain the un- 
usual increase of the moth. It is during such seasons that 
its destructiveness is most apparent. It is then that the 
groves and forests are stripped of their leaves, and whole 
rows of trees in orchards and along highways appear to have 
been stripped in a single night. 

Distribution as affected by Food Supply and other 
Natural Causes. 

If the number of gypsy-moth larvae in a given territory 
is small and their food supply is large, they do not usually 
spread of their own volition to any appreciable extent. So 
long as the supply of food is abundant and accessible the 
caterpillars usually remain on or near it, and will move only 
when disturbed or dislodged from the trees or other plants 
on which they feed. In such cases they will reascend the 
same tree or crawl to near-by vegetation. When a tree is 
overcrowded with caterpillars, and by reason of their vo- 
racity food becomes scarce, they will crawl rapidly in all 
directions in search of it, and thus they spread out from a 
common centre over a limited area. Wherever the moth is 
introduced it has the advantage of such species as the canker 
worms (Paleacrila vernata and Anisopteryx pometaria) and 
the tent caterpillar ( Clisiocampa americana) , which are con- 
fined to a few kinds of food plants. Because of the great 
number of its food plants it is capable of subsisting in almost 
any locality whereto it may migrate or be transported. Its 
spreading is, therefore, more general and its distribution less 
localized than that of the canker worms. But as the female 
moth does not fly, the species is limited in its powers of 
migration, and though the larger caterpillars are very rest- 
less, their movements show little method except when food 
becomes scarce. It has been seen that isolated colonies of 
the moth in woodlands not frequented by men do not often 
spread to a considerable extent until the caterpillars have 
increased in numbers so as to destroy all the foliage in the 
originally infested localities. They then migrate in search 
of food, and when this movement is once begun they some- 



98 THE GYPSY MOTH. 

times scatter to a considerable distance. Though this is the 
rule there are some exceptions. In some localities, presum- 
ably where the larvas are persecuted by many enemies, they 
are found scattered abroad over a considerable area even 
when food is abundant. 

The moths are sometimes distributed by birds. Many 
birds feed upon the caterpillars, and in some cases they have 
been known to drop them alive while carrying them to their 
young. As the larvse are very hardy and are likely to 
survive rough treatment, they may be scattered somewhat 
in this way. ' Some of the distribution in woodlands may 
be thus accounted for. The smaller larvse may even be 
occasionally carried a short distance on the feathers of a 
bird. The caterpillars are also occasionally transported 
by the wind. As they hang by threads from the trees 
they are sometimes swept off by sudden gusts of wind and 
carried to a distance of perhaps a hundred yards. As the 
moths are found distributed along running streams, it is 
probable that caterpillars and imagoes are occasionally swept 
down stream, and that now and then an egg-cluster is car- 
ried away on a floating piece of bark or dead twig or branch. 
Pieces of driftwood with eggs upon them have been found 
on the banks of streams and on the shores of islands in 
ponds. Egg-clusters thus exposed to the action of water 
have been known to hatch. The moth has been distributed 
in the same way along tide-water streams and even to trees 
and bushes growing on spots above the level of tide-water 
in salt marsh. Wherever the insect is numerous the eggs 
are sometimes laid on the leaves of the trees. They are fre- 
quently laid on dead leaves on the ground. In either case 
the leaves may be afterwards blown to some distance by the 
autumnal winds. Egg-clusters may be broken during gales 
by the branches of a tree beating against each other or the 
trunk, and the scattered eggs will then be blown away by 
the wind. Other ways in which distribution might happen 
will occur to those familiar with the subject. But the pe- 
culiar distribution of the moth over a region more than two 
hundred square miles in extent cannot be accounted for 
either by the movements of the caterpillars or by any of the 
foregoing causes, for there are well-marked isolated colonies 



CAUSES AFFECTING DISTRIBUTION. 99 

at a distance of a mile or more from other infested localities. 
When the action of the regulative influences which at first 
checked the increase of the moth and the limitation of its 
powers of locomotion are considered, it seems improbable 
that the moths could have spread over thirty townships in 
less than twenty years unless transported by some human 
agency. 

The Connection of Distribution and Population. 

The study of the infested territory made in 1891 showed 
that the most densely infested areas were very nearly coin- 
cident with the centres of population. In other words, the 
moth colonies were larger and more numerous in or near 
thickly populated districts. (See map IV.) It was noted 
that as the inspection receded from Medford, where the moth 
was first introduced, the towns were less and less infested. 
When, in this inspection, the centre of a town next adjoin- 
ing Medford was reached many moths were found. As the 
centre was passed they grew less numerous until few, if any, 
appeared along the highways. Such trees as were found 
infested were generally near farm-houses and other resi- 
dences. On approaching the next town the moths were 
again found in considerable numbers, although not as nu- 
merously as in the first town. After the second town was 
passed none were found upon the country roads leading 
farther out. This led to the hope that there were no 
moths in the region beyond. But an inspection of the next 
town revealed a few, while in the towns beyond none were 
found. 

Outside of Medford the moths were most numerous in 
portions of the cities lying nearest to that town, such as 
Maiden, Chelsea, Somerville and Cambridge. Next, the 
larger towns, as Melrose, Arlington, Belmont and Win- 
chester, and the more distant cities, Lynn and Salem, were 
most infested. Comparatively few moths were found in the 
more sparsely settled towns, like Lynnfield, Reading and 
Lexington. This distribution of the moth along the roads 
and over populated districts led to the assumption that 
man was accountable for its diffusion as well as its intro- 
duction. 



100 THE GYPSY MOTH. 



The Distribution of the Moth by Man's Agency. 

The distribution of the moth by man, and the means by 
which it was accomplished, will be better understood if a 
description of the territory comprised by the infested towns 
and cities is first given. 

This region extends along the coast of Massachusetts Bay 
from Boston harbor to the Beverly shore. North of Boston 
a considerable portion of the land surface next to the shore 
consists of salt marsh, penetrated here and there by tidal 
streams like the Mystic and Saugus rivers. Nahant and 
Marblehead Neck are bold, rocky peninsulas extending out 
into the sea. The Salem "Great pastures," lying not far 
from the sea, consist of rolling pasture land covered to some 
extent with a scrubby growth of red cedars and the charac- 
teristic barberry and other wild shrubs of the locality. 

A long beach extends along the outer border of the salt 
marsh from the Saugus River to the shores of Beachmont, 
and is known locally as Crescent or Revere Beach. It is a 
popular summer resort. High bluffs front the sea on the 
Winthrop peninsula, and beyond them to the south is a 
strip of gravelly shore called Winthrop Beach. A tide of 
summer travel ebbs and flows along all these shores. 

Back from the shore in the valley of the Mystic River an 
open and quite level country extends from the salt marsh 
through Medford and Arlington to the Mystic lakes, where 
the river has its source. The Charles River valley through 
Cambridge, Watertown and Waltham consists of a beautiful 
open country. A range of rocky hills traverses the north- 
central portion of the infested district and extending northerly 
and easterly from Lexington reaches the sea at Marblehead. 
At the Marblehead shore these hills are almost treeless, but 
in Swampscott and through Lynn, Saugus, Melrose, Maiden, 
Medford, Stoneham, Winchester, Arlington and Lexington 
they are more or less clothed with trees. This rocky, wooded 
region is of no great agricultural value. Portions of it have 
been reserved for public parks by the towns and municipali-. 
ties. A large tract situated in Maiden, Medford, Winchester 
and Stoneham has been taken by the State as a public forest 
reservation. This region, which is known as the Middle- 



DISTRIBUTION BY MAN. 101 

sex Fells, contains some of the finest natural scenery in the 
eastern part of the State. These rocky hills, crowned 
with a growth of pines, cedars, oaks and other characteristic 
trees, intersected by running streams with here and there 
miniature cascades and occasional reedy fens, together form 
a succession of delightfully picturesque scenes of rugged 
beauty. Woodlands interspersed with open spaces, fresh- 
water meadows, towns, villages and farming lands extend to 
the northern and western boundaries of the infested region. 
Nearly all of the southern portion of this region is occupied 
by Boston and its adjacent cities. 

The situation of the towns and cities of the infested 
region, and their relative positions, may be seen by reference 
to the map. A large proportion of the population of Mas- 
sachusetts is contained within this district.* Boston and 
the cities in its immediate vicinity lie in or near the Charles 
and Mystic valleys. It will be seen that Somerville, Cam- 
bridge, Chelsea, Maiden, Medford, Everett and Waltham 
are all cities lying in the immediate neighborhood of Boston. 
Along the shore to the north-east are Lynn, Salem and Bev- 
erly. Woburn is the only city in the north-western part of 
the district. 

The following cities and towns are comprised within the 
territory which is or has been infested : Arlington, Belmont, 
Beverly, Boston, Burlington, Cambridge, Chelsea, Danvers, 
Everett, Lexington, Lynn, Lynnfield, Maiden, Marblehead, 
Medford, Melrose, Nahant, Peabody, Reading, Revere, Sa- 
lem, Saugus, Somerville, Stoneham, Swampscott, Wakefield, 
Waltham, Watertown, Winchester, Winthrop and Woburn. 

The larger portion of the region infested by the gypsy 
moth lies north of Boston. Boston's avenues of communica- 
tion to the north and east and in part to the west run through 
it. The main lines of the eastern and western divisions of 
the Boston & Maine Railroad pass through the infested 
district but east of its centre. Several branch lines lead to 
or through different parts of the district. Two lines run 
from Boston to Medford, — the Medford branch, ending in 



* By the State census taken in 1895 (first count) the population of the cities and 
towns of the district infested by the gypsy moth is 963,159. 



102 THE GYPSY MOTH. 

the centre of the town, and the main line of the southern 
division of the Boston & Maine Railroad, passing through 
Somerville and West Medford. The old turnpike roads from 
Boston to Salem, Newbury port, Lawrence and Lowell all 
pass through the infested region. The roads which pass 
through this region from Boston lead outward toward the 
north, north-east and west. 

The continual and immense traffic between Boston and 
towns to the northward, coming and going through the badly 
infested region, together with that in and out of the region 
itself, has resulted in spreading the moth to many of these 
outer towns. This has been brought about chiefly by means 
of the transportation of caterpillars on vehicles. In the 
spring of 1889, and in other years when the moths were in 
greatest abundance in Maiden and Medford, the young 
caterpillars, when disturbed by wind or by any object strik- 
ing the branches, hung in great numbers by their silken 
threads from the trees in a manner similar to that habitual 
with the common canker worms. While suspended in this 
way above the street they were often struck by passing 
vehicles upon which they dropped, remaining either until a 
stopping place was reached or until shaken off along the 
roadside.* Regular teaming, daily or at stated intervals to 
or from a badly infested spot during the time when the 
caterpillars were very numerous on wayside trees, would 
finally result in transporting numbers of them to certain 
localities where the wagons stopped. A market gardener's 
wagon going regularly through the infested region to Boston 
and return, and passing under infested trees along the way, 
would be very likely to carry caterpillars into the yard at the 
end of the route. If a single pair of the caterpillars thus 
transported survived and passed through their transforma- 
tions, and the resulting pair of moths mated, the seed for a 
colony might be planted. Even if one female caterpillar 
survived and transformed into a moth, and there were a simi- 
larly surviving male moth in the neighborhood, under favor- 
able conditions the latter might be attracted to the former 



* All forms of the moth have been found on wagons standing under trees. The 
caterpillars frequently crawl for shelter under the bodies of standing vehicles. 



DISTRIBUTION BY MAN. 103 

and fertile eggs result. There were many ways in which 
the regular traffic with towns round about was kept up to or 
through the infested region. Florists and nurserymen Avere 
constantly sending plants to all parts of the region and to 
Boston. Truck farmers' teams hauled loads of produce to 
Boston and returned with loads of manure. Expressmen 
made their regular trips ; butchers, bakers, peddlers and 
milkmen daily went their rounds, and the premises of many 
of these people who were constantly driving about the 
infested region or through it became infested. During; the 
summer there was* much carriage driving through the in- 
fested district, especially along the North Shore, and this 
also served to distribute the moth to some extent. In addi- 
tion to the transportation of the moth in its various forms 1 >y 
means of vehicles there were other means of distribution 
more strictly local. The caterpillars were carried about to 
some extent on the clothing of pedestrians and on the backs 
of cattle, goats, dogs and other animals. 

While the spread of the moth has been mainly due to the 
transportation of the caterpillars, the eggs of the creature 
were also carried about in various ways. Wood was cut 
from infested trees and carried with eggs upon it from one 
town to another. Packing cases and barrels left under in- 
fested trees are sometimes selected by the female moth as 
receptacles in which to deposit her eggs. Barrels and cases 
which had been exposed to such infestation were not only 
shipped about through the infested region but were some- 
times sent to a considerable distance outside. If an e^ir- 

Co 

cluster laid on an article thus shipped escaped destruction en 
route, there would be danger of the seed of a new colony 
being planted at the article's place of destination. 

Instances of Distribution by Man. 
It was learned in 1891 that the area occupied by the moth 
was practically included within the boundaries of thirty town- 
ships. Since that time it has been found outside of this 
boundary in a few isolated cases only, each of which was 
accounted for by the existence of driving or teaming from 
the infested district. The moth had reached these places 
during the few years previous to 1891, when it was most 



104 THE GYPSY MOTH. 

abundant in Medford. These years of its greatest abundance 
were also the years of its greatest diffusion, for during the 
period when it was most numerous on trees, about buildings 
and along highways, many more caterpillars were carried out 
on vehicles from the worst infested localities than at any time 
before or since. From the small size and general appear- 
ance of most of the colonies found in 1891 at a distance from 
Medford, it was apparent that they had originated but two 
or three seasons previous to that time. On further inspec- 
tion it became evident that the moth had become widely 
distributed in 1888, 1889 and 1890 over the region occu- 
pied by it in 1891. 

Most of this diffusion to a distance from Maiden and 
Medford was accounted for by teaming and driving to and 
from the district originally infested. Therefore, it may be 
termed the primary distribution, as it was caused by trans- 
portation direct from the towns first infested. Here and 
there, however, large colonies were found that must have 
been growing for eight or ten years. These colonies, if on 
or near highways, had already become centres of infestation 
from which the moths had been distributed widely, not only 
along the roads leading out of the infested locality but also 
back toward the originally infested centre by means of 
vehicles bound toward Boston. This spreading from these 
colonies may be called a secondary diffusion. Of this there 
are some interesting examples. From the large colony 
in Swampscott (see page 58) the moths were not only dis- 
tributed on to Marblehead but they were 'also taken back 
into Lyun. The Lynn residence of the owner of the place 
where the Swampscott colony was situated was found in 1892 
to have been recently infested, and it was learned that the 
owner had been accustomed to drive frequently to the 
Swampscott place and leave his horse and buggy in the yard 
under the infested trees. 

Early in 1891 a colony was found in North Cambridge in 
the yard of Muller Brothers' tannery. As thirty-five thousand 
egg-clusters were taken there the colony must have originated 
several years previous to 1891. Dead horses were frequently 
carted from Maiden and Medford to the Muller place, where 
there were at that time facilities for making such use of these 



DISTRIBUTION BY MAN. 105 

remains as was compatible with their character, age and 
general utility. It is probable that the moths were originally 
carried there on the wagons which were used for this dolo- 
rous traffic. The Cambridge almshouse was situated a few 
rods in the rear of the tannery. The city swill was hauled 
from all parts of Cambridge to this almshouse and was then 
distributed for miles around to farmers and others who kept 
hosjs. These swill-takers' wagons in going and comma; were 
obliged to pass under the branches of some badly infested 
trees that overhang the street. A tide-water stream ran 
through the tannery yard. An inspection revealed that the 
trees along the stream for many rods were infested. Here 
was a secondary centre of distribution of the first magnitude. 
Persistent efforts were made to stamp out this colony. When 
this had been done the locality was carefully watched. As 
the country roundabout was inspected the moths were found 
scattered all over neighboring portions of Cambridge, Somer- 
ville and Arlington. In 1893 a list of the persons to whose 
places swill had been teamed was secured from Capt. M. L. 
Eldridge, superintendent of the almshouse. This comprised 
the names of nearly three hundred people residing in the 
following towns : Arlington, Bedford, Belmont, Brighton, 
Burlington, Cambridge, Carlisle, Concord, Lexington, Lin- 
coln, Medford, Somerville, Waltham, Watertown, Weston, 
Winchester and Woburn. The places of more than fifty 
people in the list have since been found to be infested. The 
results of the investigation did not indicate that in all cases 
they had become infested by the carriage of swill, for it was 
seen that some places to which swill had been hauled during 
the months when the caterpillars were numerous upon trees 
were not infested, while others to which swill had been hauled 
in the winter only were infested. Yet it seems probable from 
all the data obtained from inquiry in these localities that 
more than half the infested places had received infestation 
from the hauling of swill from the almshouse. 

Localities in the infested district that are much visited on 
account of their historical associations are usually found in- 
fested, and if cleared of the moth are likely to become re- 
infested. Many eminent men have been buried in Mount 
Auburn Cemetery, which lies partly in Cambridge and partly 



106 THE GYPSY MOTH. 

in Watertown. This cemetery is often thronged with visitors 
from far and near. It was well cleared of the moths in 1892 
and 1893, but in 1895 the caterpillars appeared again in 
such quantities near the graves of the poets Lowell and 
Longfellow that much effort was required on the part of the 
workmen employed by the Board to prevent serious injury 
to the trees in the cemetery. Though Charlestown was 
cleared of the moths in the first three years of the work, 
they were found in 1895 at Monument Square. These 
grounds about Bunker Hill monument are much frequented. 
Many people coming from other parts of the infested region 
have visited the monument within a year. The carnival in 
Charlestown on the 17th of June, a time when the cater- 
pillars are most numerous, draws thousands of people from 
the region round about to the vicinity of the monument. 

A Study of the Methods and Routes of Trans- 
portation. 

In 1891 hasty inspection of the infested region finally 
revealed its apparent extent. This inspection was carried 
on until, in 1893, a wide belt around the region had 
been examined. The question whether the moths had been 
transported to any distance beyond this belt in sufficient 
numbers to continue the existence of the species and thus 
form other centres of distribution remained unsolved. It 
was not possible under the appropriations made to extend 
the search over the entire Commonwealth. As it was evi- 
dent that the moth was distributed principally by man, a 
study was made first of the nature and direction of the 
traffic and travel which had caused the dissemination of the 
moth through the region known to be infested ; next a study 
was made of such similar traffic as extended to a distance 
from the infested region and which, therefore, might expose 
other localities to infestation. 

In studying methods of transportation special attention was 
paid to the steady and constant traffic back and forth between 
points within and without the heart of the infested district. 
Information was also secured as to the character, routes and 
destination of outward freight shipments by road and rail, 
and of the vast miscellaneous traffic and pleasure driving 



DISTRIBUTION BY MAN. 107 

over the road. Inquiries were first made in the inner and 
worst infested towns. Supplementary and additional infor- 
mation was gathered later outside the infested district in those 
localities known to have had more or less communication with 
the "danger tract" of the infested region during the greatest 
prevalence of the moth. This ' ' danger tract" was the heart of 
the infested region (Medford and Maiden) because the swarm- 
ing numbers of the caterpillars there had made possible their 
frequent transportation by vehicles to other points. At first 
there was not so much danger of such transportation from 
anywhere else in the infested district because of the com- 
parative scarcity of the moths in other localities and the 
usual small size of their colonies. This study shed a flood 
of light upon the manner of the distribution of the moths in 
the territory originally infested from Medford, and explained 
the existence of many colonies in woods and other retired 
places. It also indicated the places which had been most 
exposed to infestation in the territory lying beyond the 
known limits of the moth's spread. 

The investigation of the transportation of the moth was 
confined mainly to the traffic and communication to the north, 
east and west of Medford. The great bulk of all driving over 
the road and the still greater proportion of " dangerous" or 
constant traffic was to the north and west and along the 
North Shore to the north-east, and consequently the moth 
had been diffused farther in those directions. There is little 
constant and direct teaming traffic to any other southern 
point than Boston, and the latter place,, by reason of the 
small number of trees in its business sections, was a com- 
paratively safe point for the reception of such traffic. 

In the inquiry in regard to the traffic over the road, all 

information possible was obtained concerning the routes of 

expressmen and movers, market-gardeners, farmers, milk, 

hay and w r ood dealers, swill-takers, butchers, peddlers and 

junk men. Local boards of health and milk inspectors in 

and around Boston furnished information by means of which 

those engaged in the milk business and in swill taking were 

» . . . 

located and their routes ascertained. Much information was 

secured in regard to the great market-gardeners' traffic over 

the road between Boston and towns within the infested district 



108 THE GYPSY MOTH. 

or to the north and west of it. Information was sought in 
regard to excursions and picnics to the groves situated on all 
sides of the worst infested district. Much knowledge was 
obtained in regard to the grounds used by church and Sunday 
school picnic parties from Maiden, Medford, Revere, Somer- 
ville, Cambridge, Arlington, Melrose, Lynn and Everett. 
Places of great public resort, like militia and camp-meeting 
grounds, were also noted and were later examined. Facts 
bearing upon the hauling of wood to or through the infested 
district were carefully gathered. Inquiries were made of 
expressmen and movers in regard to the destination of families 
which had moved from badly infested localities, and as to 
the large amount of summer moving and teaming along the 
North Shore, and the amount of teaming over the road weekly, 
monthly or yearly between the infested district and centres 
of traffic like Lawrence and Lowell. The matters of ship- 
ments of nursery stock and greenhouse plants over the road 
and of towns visited and routes taken bj r peddlers and junk 
dealers were also investigated. A vast amount of facts 
bearing on the subject of miscellaneous driving was also 
obtained. The inquiry was not entirely confined to the 
heart of the infested district but was extended to less infested 
places like Lynn and Salem. The scope of the whole in- 
vestigation quickly broadened. Clues obtained within the 
infested district were followed out, and this led to much 
additional inquiry in many towns to the north-east, north 
and west of the infested region. Every possible fact and 
item bearing upon the subject of communication with the 
moth-region were obtained. It was not difficult in country 
towns to learn who were the regular and who the occasional 
visitors to or from the infested district and what was the 
nature of their business. The lines of travel were also easily 
learned. In cities like Lawrence and Lowell which, although 
farther away, were in a sense exposed because of their being 
centres of population, lists were obtained of teamsters and 
movers who went more or less frequently to the district to 
the south and the character of their business was learned. 
These local teamsters as a rule made their return trips empty 
handed, and thus the danger of moth transportation, except 
by the vehicle itself, was avoided. 



DISTRIBUTION BY MAN. 109 

The investigation and the subsequent inspection based 
thereon revealed the important fact that the most dangerous 
traffic was that going only a short distance from the centre 
of the infested district. A large proportion of this did 
not even go out of the district, and nearly all the re- 
mainder went but little farther. The proof of this is ample. 
The most dangerous traffic is the steady and constant traffic 
back and forth between the same points which, by its regu- 
larity, makes possible the occasional transportation of cater- 
pillars to the same locality. This regular traffic includes the 
trips of market-gardeners, farmers, milkmen, swill-takers 
and others living in the outer towns of the infested district 
or in the towns next beyond, who go daily or weekly in and 
out of the heart of the infested district or through it to 
Boston and return. Nearly all of the foregoing classes of 
people live comparatively near the heart of the infested dis- 
trict. None of them live very far away. In a word, in 
proportion as the distance from the heart of the infested dis- 
trict increased, the regularity and frequency of traffic to and 
fro decreased, and in the same ratio the danger of moth 
transportations and consequent possible establishment of new 
colonies diminished. The work of four years has proved 
that new colonies at a distance from the infested centre 
have owed their origin and rise, not to a single transportation 
of the moth but to various cases of the sort which have 
been made possible by steady communication over the road 
between two points. Even pleasure driving, when con- 
stant and frequent between an infested locality and one out- 
side, has been responsible for the establishment of a new 
colony. 

In the study of traffic and driving of all sorts over the 
road, the question of routes became of the utmost impor- 
tance. The vast aggregate amount of wheeling by its very 
existence caused the roadsides of all main highways and the 
neighborhoods of hotels, village stores, blacksmith shops 
and watering troughs to become more or less exposed, the 
danger, of course, decreasing as the distance increased from 
the infested district. There were two reasons for this : 
first, the great bulk of all wheeling, miscellaneous as well 
as regular, did not go to a great distance ; second, the ma- 



110 THE GYPSY MOTH. 

jority of larva? transported on vehicles are undoubtedly shaken 
or brushed off before many miles are traversed. 

The possible danger attaching to freight shipments by rail 
from Maiden and Medford was investigated by an examina- 
tion of "freight forwarded" books at the various stations. 
The examination of these books revealed the origin, character 
and destination of shipments since 1880. The origin and 
character of shipments immediately revealed the danger, if 
any, attaching to them. To illustrate : Manufactures and 
household goods, constituting the bulk of shipments, com- 
ing as they do from in-doors, are practically safe shipments ; 
while articles which have been exposed out of doors, such as 
empty boxes, nursery stock, bricks, stones, scrap iron or 
builders' materials, may, if coming from an infested locality, 
be dangerous shipments. In this connection the matter of 
date of shipment was important. Some articles, by reason 
of their place of origin, might be dangerous shipments only 
during the larval season ; others, only during the months 
when the eggs arc the only living form of the moth. Fi- 
nally, the examination of the freight books revealed the 
receivers of goods (whether in or out of the infested district) . 

The danger of moth transportation on freight sent by rail 
was shown by the investigation to be very slight. The 
proportion of shipments which on account of their character 
or frequency might be considered as dangerous was extremely 
small.* The destination of these being known, it was possible 
to do supplementary work in the nature of inquiry and 
inspection at these points of destination. In most cases such 
work was done. 

The matter of shipments of bricks from Medford deserves 
special mention in this connection both because of its intrinsic 
importance and as an illustration of the methods of inquiry 
pursued. The premises of the Anderson Pressed Brick 
Company were in the past badly infested. Shipments of 
brick had been made to many points outside the infested 
territory. Most cases were investigated and an inspection 
made at the places to which the brick had been shipped. In 
this work the agents of the Board visited a number of towns 

* This is equally true of freight shipments over the highway. 



DISTRIBUTION BY MAN. Ill 

widely scattered over the State. Although the danger of 
the transportation of the moth in the egg form had appeared 
serious, no trace of the insect was anywhere found.* 

In addition to the freight shipments, another danger of 
moth transportation lay in the possibility of the cars them- 
selves carrying some form of the moth. This might happen 
in case a car had stood for some time on a siding near infested 
trees or other objects. Two instances are recorded where 
egg-clusters have been found on freight cars standing on 
sidings. This led to an inquiry into the condition of rail- 
road sidings, whether treeless or not, and if the latter, 
whether infested or not. It was obvious that if moths were 
transported by cars and new colonies started, these would 
be found along the lines of railroad, probably at sidings and 
stations. This later led to the inspection, as a measure of 
precaution, of the lines of railroad running north and west 
out of the infested district, the eastern and western divisions 
of the Boston & Maine road being followed out as far as 
Portland, Me., the southern division as far as Concord, N. H., 
and the Fitchburg road as far as Fitchburg. In the matter of 
possible danger of moth transportation by cars, the shipment 
of wood to the Bay State Brick Company in Medford de- 
serves mention. The premises of this brick company are 
infested. Thousands of cords of wood are shipped there 
yearly from New Hampshire points, and the same platform 
cars were in the past often sent back and forth again and 
again. A certain amount of danger had unquestionably 
attached to this species of traffic. The places of shipment 
in New Hampshire were consequently visited and the sidings 
in their neighborhood carefully examined, but no trace of the 
moth was found. In this work additional information was 
secured whenever possible as to any communication between 
outside points and the infested region. This inspection of 
suspected localities outside the State was rendered necessary 
in connection with the policy of extermination, which pro- 
ceeded on the theory that the moth was confined to a limited 
area in the State of Massachusetts. 



* The danger of transportation of eggs was lessened by the fact that the finest 
bricks, the only ones sent to a distance, were cleaned before being shipped. 



112 THE GYPSY MOTH. 

At the height of the caterpillar plague in Medford, it is 
said that it was almost impossible for people going through 
the streets leading to the Glenwood station of the Medford 
branch railroad to avoid carrying caterpillars which dropped 
down upon their clothing from the wayside trees. (See the 
statement of Mr. Sylvester Lacy on page 17.) As the rail- 
road ran only from Medford to Boston, there was not as 
much danger of the caterpillars being transported to a dis- 
tance by means of the luggage and clothing of passengers 
as there would have been had the railroad passed through 
Medford to other parts of the State or to other States. 
Nevertheless, during 1888, 1889 and 1890 very many cater- 
pillars undoubtedly were carried in this way not only to 
Boston but to other parts of the State. Even in 1891 cater- 
pillars were thus frequently carried. An agent of the Board 
of Agriculture stated to the writer that in 1891 he took a 
gypsy-moth caterpillar from the cloak of a lady standing in 
front of the ticket office in the western division station of 
the Boston & Maine Railroad in Boston. The lady had 
come from Medford and had just bought a ticket for North- 
ampton, a city in the Connecticut valley. Had the cater- 
pillar not been removed from her cloak, it might have been 
carried a long distance, or if left upon the cars it might have 
escaped observation, dropping off eventually at some point 
along the road. If such cases have frequently occurred the 
question at once arises, why have not moth colonies been 
formed far and wide? While at first sight it would seem 
probable that they have been thus formed, yet upon con- 
sideration it is seen that the carriage of caterpillars in this 
way to a distance is not necessarily dangerous. The farther 
a caterpillar is carried from others of its kind the less be- 
comes the probability of its reproduction. The female moth 
does not fly. With favoring winds in open country the male 
can find the female, by means of his sensory organs, at a 
distance of about half a mile. The change of cars which was 
necessary in Boston, and the radiation of the railroads to the 
north, east, south and west, served to decrease the chances 
of propagation, for the farther a caterpillar was carried from 
Boston the greater became the distance which separated it, 
not only from the infested region, but from other lines of 



DISTRIBUTION BY MAN. 113 

railroad leading out of Boston on which other caterpillars 
might be carried out. Thus, though many caterpillars might 
be accidentally carried to a long distance outside the infested 
region, there was very little probability that any number of 
such individuals would be dropped within half a mile of each 
other. Furthermore, the chances that isolated caterpillars 
would complete their transformations and emerge as perfect 
insects are very small. Therefore, there would be hardly a 
possibility of a colony being started by the accidental trans- 
portation of caterpillars to a distance unless it should be 
proved that parthenogenesis (the reproduction of the species 
by the virgin female) occurs.* If, however, the moths should 
at any time become abnormally numerous on the line of an 
extended railway, their chances of accidental distribution by 
regular and constant travel would greatly increase and a 
wide dissemination would almost certainly follow. So far, 
notwithstanding the unhindered carriage of caterpillars in 
this way on the Medford branch railroad for several years 
previous to 1892, no evidence of the moths' existence at a 
distance from the infested towns has ever been found alon«: 
the lines of other railroads. 

The Effect of the Work of Extermination on the 
Distribution of the Moth. 

While the work of destroying the gypsy moth has much 
reduced the numbers of the moths and the extent of territory 
occupied by them, it has been necessary to exercise great care 
to avoid accidental distribution of the caterpillars by the 
workmen. 

The work of spraying is responsible for some slight local 
scattering of the caterpillars. When the branches of a tree are 
disturbed by the sprayers, many of the caterpillars spin down 
and either fall to the ground or are carried about upon the 
clothing of the workmen or others passing beneath the tree. 
Unless great care is taken they may be carried from place to 
place on the spraying team. Those falling to the ground 

* Observations so far made in this country have not revealed a case of partheno- 
genesis in this species, but, on the contrary, many instances have shown isolation 
to result in extermination. A few European instances of parthenogenesis have been 
recorded. 



114 THE GYPSY MOTH. 

frequently crawl to other trees, and if later these trees are 
sprayed many of the caterpillars crawl still farther. It is 
almost impossible to avoid scattering the moths when spray- 
ing is resorted to, which makes it necessary to spray all 
vegetation near an infested spot, that the scattering cater- 
pillars may find poisoned food. 

As the work of burlapping has progressed since 1891 the 
proportion of caterpillars seeking the shelter of the burlap 
appears to have diminished. Many either remain in the 
tops of trees or seek out places near the ground in which 
to secrete themselves. There also seems to be a tendency 
to scatter farther and farther from the infested localities. 
These habits may have been induced by the frequent dis- 
turbing of the caterpillars in the work of burlapping, or here 
may be another illustration of the survival of the fittest. 
When the caterpillars are very young and while the workmen 
are placing the burlap bands about the trees they are likely 
to dislodge some of the caterpillars which, felling upon their 
clothing, may be carried about from place to place. To lessen 
the risk of such carriage the workmen in summer are dressed 
in a uniform suit of a light color so that any dark object 
falling upon them may contrast strongly with their clothing. 
The men are also cautioned to examine carefully each other's 
clothing when leaving an infested place. Notwithstanding 
this precaution it is possible that a few localities from which 
the moths have been entirely exterminated have become re- 
infested in this way, for occasionally a place in which no 
form of the moth has been found for a year or two becomes 
again infested. In such cases from one to three or four 
caterpillars have been found during the season, not a suffi- 
cient number to indicate that eggs had been laid there in the 
previous season. 

The Distribution Restricted and Changed. 
As far as the work of extermination has proceeded it has 
radically changed the distribution of the moth. It is often 
the case that the most persistent and thorough work will not 
exterminate the moths from a locality in one year. It is 
necessary to search a locality for several years in order to 
be assured that the moths are all destroyed and no seed is 



ITS DISTRIBUTION CHANGED. 115 

left. But we have now sufficient data for the belief that the 
moths found in most colonies in the outer towns in 1891, 
1892 and 1893 have been exterminated. In this way the 
outward spread of the moth to new territory has been 
restricted. It has been necessary, as a part of the policy pur- 
sued in preventing the spreading of the moth towards towns 
outside the boundary of the infested region, to search carefully 
the borders of highways and streets in towns and cities, as it 
was from cultivated grounds in populous towns and by high- 
ways leading from the towns that the moths were mostly dis- 
tributed. As the moths in the woods spread slowly, and were 
less liable to transportation outside the infested region than 
those in the residential and business sections, work was con- 
centrated upon these districts to the neglect of the woodland. 
As has already been stated, the centres of distribution in 1891 
coincided with the centres of population, and in the attempt to 
clear these centres and prevent injury to valuable trees and 
plants the larger part of each appropriation was used. From 
what was learned yearly by the woodland searchers it was be- 
lieved that the moths were increasing and spreading in the 
woods. The committee in charge of the work stated this be- 
lief year after year to the legislative committees and strongly 
urged in their reports to the Legislature that more money be 
appropriated for the inspection of the woodlands and the 
destruction of the moths within their borders. Sufficient 
appropriations not being forthcoming the result of the neg- 
lect of the woodland is now shown in the present distribution 
of the moth. The normal diffusion from centres coinciding 
with the centres of population has given place to a much 
slower dissemination from centres situated in the woodlands 
of the north-central infested towns. Though much work 
has been done in these woodlands it has been from necessity 
superficial and has merely resulted in partially holding the 
moths in check. In some localities where the woods were 
not searched the increase and spread have been unimpeded 
because the colonies were not known. 

In the report of the work of the year 1894, made by the 
Board of Agriculture to the Legislature, it was stated as 
probable that the moths were scattered through the woods 
from Lexington to the sea. That this probability has be- 



116 THE GYPSY MOTH. 

come a certainty is shown by the developments of the season 
of 1895. As has before been stated, there are in this region 
three centres of infestation of at least a thousand acres each. 
(See page 87 . ) These centres are included in a belt of wood- 
land a mile in width, which is all more or less infested, 
reaching with some interruptions from East Lexington to 
Salem, a distance of about eighteen miles. 

As compared with 1889 the moths in open and cultivated 
lands are now much reduced in numbers in the worst in- 
fested sections and are elsewhere extinct or comparatively 
rare. On the other hand, in the belt of woodland north of 
the centre of the infested region they occupy more ground 
than in 1889, and the number of badly infested places is 
greater. 



THE DESTRUCTION OF THE EGGS. 117 



Methods Used for Destroying the 
Gypsy Moth. 

The Destruction or the Eggs. 

As the egg-clusters of the gypsy moth are of a conspicuous 
color and may be found upon trees and other objects during 
at least eight months of the year, the possibility of stopping 
the moth's increase by destroying great numbers of cater- 
pillars in embryo becomes apparent. In each buff egg-cluster 
temptingly displayed upon the tree trunks during the fall, 
winter and spring there are from three hundred to fourteen 
hundred potential caterpillars. Destroy the egg-cluster and 
apparently you have disposed of the coming, brood. You 
have prevented the hatching of the eggs and the consequent 
spreading of the caterpillars which otherwise would have 
scattered abroad, feeding upon nearly all kinds of trees, 
shrubs and garden plants. Obviously it is safer, easier and 
less expensive to destroy the egg-cluster in which the brood 
is united and stationary than to find and destroy the cater- 
pillars after they have hatched and scattered. The destruc- 
tion of eggs may not always secure extermination, as the 
female imago sometimes scatters fertile eggs upon the ground, 
and concealed egg-clusters may sometimes be overlooked. 
Yet persistent and thorough egg-destruction in the autumn, 
winter and spring may be relied upon to so reduce the num- 
ber of the moths that they will do comparatively little injury 
in the ensuing summer. Egg-killing is recommended by 
many European authors as the first and chief method of pre- 
venting the ravages of the moth. 

Bechstein wrote in 1804: "The clusters of eggs can be 
looked for from the last of September or October to March, 
upon the trunks of trees, walls, hedges and fences, and may 
be crushed or knocked off into a pot and burned by kindling 
a fire upon them." * 

Canon Schmidberger, who wrote the papers on ' * Insects 

* " Vollstandige Naturgeschichte der schadlichen Forstinsekten," Leipzic, 1804, 
page 372. 



118 THE GYPSY MOTH. 

Injurious to Fruit Trees " for Vincent Kollar's work, pub- 
lished at Vienna, Austria, says : " With respect to destroy- 
ing these insects, the first thing that is necessary is to find 
out the egg-masses and destroy them."* 

This method is quite generally employed in European 
countries where the gypsy moth is plentiful. We have con- 
ducted a considerable foreign correspondence to determine 
what methods are now in use in European countries to check 
the ravages of the moth. Under date of Aug. 29, 1895, 
Dr. Antonio Augusto Carvalho Monteiro writes from Lis- 
bon, Portugal: "We generally endeavor to kill the larvae 
at about the end of June, or to destroy the cottony discs 
which enclose the eggs during autumn, by scraping the 
trunks of the trees, the walls, etc., and then crushing or 
burning them, or sometimes even covering them with a 
thick layer of coal tar by means of brushes." 

Professor Henry of the School of Forestry at Nancy, 
France, writes under date of July 27, 1895: "The best 
thing to do is to kill the heavy female wherever it is met 
with, and especially to coat the egg-clusters, generally very 
easily seen, with a thick coat of tar by means of a brush at 
the end of a pole." 

Prof. N. Nasonov writes from Warsaw University Mu- 
seum of Zoology in Kussia, Aug. 7, 1895, stating that the 
first method used is scraping the bark from the trees after 
the deposit of the eggs. 

Prof. Max. Fingerling writes from Leipzic, Germany, on 
Aug. 9, 1895 : " The best method of holding the insects in 
check is by destroying their eggs. In this particular case 
nature has provided a means in the easily recognizable egg- 
clusters." 

When in 1891 the people of the infested region were con- 
sulted by the agents of the second commission for the exter- 
mination of the gypsy moth, it was found that there existed 
among them a strong prejudice against spraying, and also a 
belief that it was not effective with the gypsy moth. Gather- 
ing the eggs was believed by those who had fought the moth 
in Medford to be the most effective method of destruction 



* " A Treatise on Injurious Insects," by Vincent Kollar, English translation by 
J. and M. Loudon, London, 1840, page 202. 



BURNING THE EGGS. 119 

then in use. Egg-killing was begun by the commissioners, 
who, fearing that spraying might not prove effective, deter- 
mined to leave no stone unturned, but to give all promising 
methods a thorough trial. 

Burning the Eggs. 
Professor Fernald had recommended in 1889 that the eggs 
of the moth be scraped from the trees and burned. This 
was the most effectual method of egg-killing pursued by the 
first commission. During the spring of 1891 it was used 
by the second commission and later by the employees of the 
State Board of Agriculture. The eggs were scraped off or 
cut away from the objects upon which they rested, placed in 
tin cans and burned in stoves or brush tires. A fierce heat 
is required to ensure their destruction. When exposed to 
such heat they finally burst with a snapping like a bunch of 
miniature fire-crackers or the cracking of corn in a popper. 
Whenever the eggs were very numerous in undergrowth or 
waste land, fire was run through the dead leaves and debris 
as an experiment ; but this method seemed to have little 
effect, as the heat was not sufficiently intense. The hairy 
covering of the egg-clusters seems to possess remarkable 
non-conductive properties, rendering the eggs almost imper- 
vious for a time to sudden intense heat. Even with the 
hottest fire that can be applied to the egg-clusters, some 
minutes are required to destroy them utterly. A running 
brush fire merely scorched the outside of the cluster, killing 
perhaps a few of the eggs in the external layer, but leaving 
the majority uninjured. Experiments were next made with 
crude petroleum, by spraying it over the ground and vegeta- 
tion by means of watering pots and then igniting it. The 
fire thus made was fierce enough to destroy the small under- 
growth and the upper layer of leaves, together with most 
of the eggs, but such egg-clusters as remained under roots 
or rocks were not injured. Considerable oil was wasted by 
soaking into the ground, and the remainder did not give 
the degree of heat which is obtained by atomizing. Experi- 
ments were then made with a view of perfecting a burning 
machine which would incinerate all undergrowth in a given 
tract. The first experiments were not entirely successful, 



120 



THE GYPSY MOTH. 



as the machines were either too cumbersome or could not 
be used on rough or uneven ground. It was found necessary 
to provide an apparatus which would distribute the oil in 
a spray, as when thus thrown in fine particles in the air and 
ignited, it formed an extremely hot gas flame and was con- 
sumed to the best advantage. For economy's sake such an 
apparatus must be light enough to be carried and operated 
by two men, as wagons could not be driven over much of 
the ground upon which this work was done. Experiments 
were made with the cyclone nozzle. ( Plate XXVII. , Fig. 2. ) 
An oil spray from this nozzle when ignited was found to 
give a very hot and effective flame. Crude oil was first 

used as a burning 
fluid, but as it is 
very objectionable 
on account of its 
rank odor, ' ' paraf- 
fine gas " oil was 
substituted later. 
This oil has less 
odor and burns to 
better advantage , 
but is somewhat 
more expensive. A 
fifteen-gallon tank 
which could be readily carried about by two men was pro- 
vided. On such a tank a Johnson pump with a fine strainer 
placed over the .suction pipe was mounted, and a short 
hose of the kind made for the delivery of oil was attached. 
Ordinary rubber hose is worthless for such a purpose, as it 
is soon destroyed by the corrosive action of the oil, and in 
the mean time the disintegrated particles frequently clog the 
nozzle.* A pole, consisting of an iron pipe twelve feet 
long, braced by being surrounded by wood for three-fourths 
of its length, was coupled to the hose. (See Fig. 1.) No 
solder could be used in the fittings of the pipe or nozzle, 




Fig. 1. The cyclone burner. 



* The best " oil hose " that can be obtained will soon become corroded, clogging 
the nozzle. If an " automatic clearing nozzle " could be devised which would with- 
stand the heat, much time might be saved which is now necessarily used in clearing 
the nozzle. 



BURNING THE EGGS. 121 

as the fierce heat of the flame would fuse it. The wooden 
cylinder into which the pipe was thrust was one and one- 
fourth inches in diameter. The wood, being a non-conductor 
of heat, was of great convenience in handling the pole. The 
end of the pipe was fitted with a cyclone nozzle. The aper- 
ture of this nozzle is very small, hence the value of the 
strainer before mentioned, which prevents the entrance of 
foreign substances with the oil and a consequent clogging 
of the nozzle. The two men handling this apparatus filled 
the tank with oil and then carried it to the spot where the 
burning was to be done. One man then operated the pump 
while the other handled the pole and nozzle. As soon as the 
pump was started a fine spray of oil was thrown into the air 
and ignited by a match. By means of the pole the resulting 
fierce flame was carried among the undergrowth and over 
the ground, destroying every living thing in its path. When 
this work was carefully done, no eggs escaped except such 
as were hidden in ledges or holes in the ground. An at- 
tempt was made also with this apparatus to destroy eggs 
which had been deposited in stone walls. (See Plate 
XVIII.) Though this was partially successful in so far as 
the fire reached and destroyed most of the eggs, those which 
were deposited under the lower stones of the wall were un- 
harmed, even though in many cases the stones were cracked 
and broken by the heat. As it sometimes became necessary 
to use this apparatus in burning out walls near growing 
crops, a sheet-iron screen was set up between the flame and 
the growing vegetables to protect them from the heat, being 
moved along the wall as the work progressed. Burning 
was thus done without any resultant injury to the gardens. 
This machine, which has been christened the " cyclone 
burner," would be most useful in checking invasions of 
crawling pests like the army worm. 

Fire was also used in hollow trees, the eggs hidden within 
them being destroyed by burning out the decayed wood. If 
this is judiciously done, there will be no injury to the tree. 
Unless great care is used, however, to extinguish the flame in 
time, there is much danger of destroying apple trees in this 
way. Cherry, oak and willow trees have rarely been injured 
by burning out cavities ; indeed, some old trees appear to 



122 THE GYPSY MOTH. 

have been benefited by such burning, as they have shown a 
better growth during the season following. Oil is poured 
in at the top of the hollow, and a sufficient aperture made 
at the bottom to ensure a good draft. The oil is then 
lighted, and the draft in the funnel thus made fans the 
flame until the decayed wood has been consumed. This 
should be done only in the winter, when the sap is dor- 
mant, and the fire should be extinguished before it has done 
serious injury to the live wood. This treatment is unnec- 
essary in cavities so accessible that the eggs and dead wood 
may be removed by other means. 

The naphtha burner, an instrument commonly used by 
painters and plumbers, was used in 1891 as a substitute for 
the scraping of eggs from trees and rocks, which sometimes 
resulted in their being scattered. This burner is supplied 
with an air pump, and furnishes an air-blast flame of an ex- 
tremely fierce heat. If this flame is applied directly to the 
egg-cluster, it will reduce it to ashes on the tree, although 
occasionally eggs exposed to such great heat will burst, 
possibly scattering others. The burner should be used only 
on the trunks of large trees having thick bark, or in such 
cavities in trees or rocks as cannot be reached by other 

methods. 

Killing the Eggs with Chemicals. 

Early in the work of 1891 it was seen to be impossible to 
detach the egg-masses from their various places of deposit 
without occasionally scattering and losing some of the eggs. 
Experiments made during the following winter proved that 
eggs scattered and exposed to the vicissitudes of the season 
were not all destroyed by frost or snow, but that about two- 
thirds of them hatched in the spring. It was seen that it 
would be wiser and safer to destroy the eggs without re- 
moval, and experiments were made with that end in view. 
The most successful method at first used was the application 
of acids which in combination destroyed the eggs. The 
apparatus was designed and the method invented by Mr. 
F. C. Moulton, a chemist employed in the gypsy-moth work. 
The apparatus (Fig. 2) was composed of a small tin case hold- 
ing two bottles, each of them having a rubber stopper with 
two glass tubes, each of which projected into the bottle as 



USE OF ACIDS AND CREOSOTE. 



123 




Fig. 2. Acid apparatus. 



well as out at the top of the cork, where it was bent at a 
right angle. One of the tubes in each bottle was drawn 
down to a point with a small aperture, 
and served as a discharge pipe. The 
other was connected with a rubber tube 
having a mouth-piece of glass. One 
of the bottles held a mixture of phenol 
or carbolic acid and turpentine (fifty 
per cent, of each) ; the other, chemi- 
cally pure nitric acid. By blowing into 
the mouth-piece of the bottle containing 
the carbolic acid mixture, a jet of this 
acid was thrown upon the egg-mass. 
This carbolic acid at once penetrated 
the cluster and in all probability de- 
stroyed the life of the eggs. To render 
the destruction of all the eggs an abso- 
lute certainty, a jet of nitric acid from the other bottle was 
then thrown in the same manner upon the mass. While 
nitric acid of itself will not penetrate the egg-clusters, it is 
alone sufficient to kill the eggs if they are divested of their 
hairy covering and immersed in it. The two acids in combi- 
nation reacted and produced an extreme heat and corrosion, 
and a few applications entirely destroyed the egg-cluster. 

While this apparatus was being used in the field, experi- 
ments were made to find some simpler method of destroying 
the eggs. Although the acids were effective, they were 
expensive and there was some danger of injuring the men 
using them. Clothes, ropes, tools and apparatus were also 
injured by the fumes of acids which were kept with them in 
the tool boxes. The experiments finally resulted in the choice 
for use in the field of a cheap creosote oil manufactured by 
the Carolina Oil and Creosote Company, Wilmington, N. C. 
This oil was recommended for trial by Prof. N. S. Shaler. 
It requires neither preparation nor complex apparatus, but 
can be drawn from the barrel into cans and applied with a 
brush. If a cluster is thoroughly soaked with this liquid, it 
penetrates and kills all the eggs, and is very effective except 
in the coldest weather, when it may sometimes thicken. It 
may then be made more penetrative by being mixed with 



124 



THE GYPSY MOTH. 



carbolic acid and turpentine, as follows : creosote oil, fifty 
per cent. ; carbolic acid, twenty per cent. ; spirits of turpen- 
tine, twenty per cent. ; coal tar, ten per cent. The coal tar 
is always added to color the egg-clusters, so that those which 
have been treated may be distinguished. The creosote itself 
is not strongly colored, and often fades after application, 
leaving the egg-clusters of their original color. Tar is used 
in preference to ordinary pigments because it mixes well 
with the creosote, and does not settle to the bottom of the can 
but is held in suspension. Almost any mixture of sufficient 
penetrative qualities and containing considerable carbolic 
acid will kill the eggs. 

A pocket receptacle has been devised for convenience in 
carrying paint and creosote and applying them to infested 
objects. This consists of a tin can or box (Figs. 3 and 4) , in 
which two tubes are fastened. One of these tubes contains 
creosote and the other white paint. Each of these tubes is 
stopped at the mouth by a cork through which the handle of a 
small paint brush is thrust. The space inside the can and about 
the tubes is packed with cotton waste (Fig. 4), Avhich receives 
all drippings from the tubes. Paint and creosote can be 
carried thus in the pocket with little danger to the clothing. 





Fig. 3. 



Paint and creosote 
can.* 



Fig. 4. A sectional view, show- 
ing manner of packing. 



When a tree or other object is found infested, it is marked 
with paint to indicate the fact. The egg-clusters are then 
treated with the creosote. In woodland in outer towns each 



* Every tool issued to workmen in the field has its number stamped upon it. 




PLATE XIX. Treating egg-clusters with creosote. 



IMPLEMENTS USED. 



125 



eggr-cluster when treated is surrounded with a ring of white 
paint to prominently mark its location, (see Plate XIX.). 

The most recent preventive method used in Europe is the 
covering of the eggs with a coat of tar or with raupenleim, 
a substance much used to prevent caterpillars from ascending 
trees. Though these substances, as well as varnish, have 
been used here experimentally with some success, the use 
of creosote oil is much to be preferred, as it penetrates the 
eggs at once and destroys their life, while the other sub- 
stances merely prevent the larvae from emerging, provided 
the covering remains intact. 

Destroying the Eggs by Gases. 
Experiments were made to find some agent other than fire 
that would destroy the eggs in hollow trees. A little bro- 
mine or chlorine poured into the hollow of a tree, branch or 
stump will destroy all animal life within the hollow if the 
cavity can be thoroughly sealed or closed. 



Implements used in the Search for the Eggs. 
Each inspector is provided with a small binocular glass of 
opera size, which he carries in a leather case suspended by a 
strap from his shoulder. By means of this he is able while on 
the ground to distinguish the eggs of the gypsy 
moth from those of other insects when attached 
to the higher limbs of large trees. This glass 
is useful in dark or cloudy weather, as well as 
in the morning or evening twilight of the short 
winter days. Its use often renders tree climb- 
ing unnecessary, and thus much time is saved. 
Each man is provided with a pocket mirror so 
constructed that the glass, if broken, can be 
quickly and cheaply replaced (Fig. 5). This 
is extremely useful in many ways during the 
search for eggs. Whenever the lower rail of a 
board or picket fence is so near the ground that 
its under side cannot be seen, a mirror placed at 
a slight angle underneath will reflect the whole 
lower surface for several feet, and show any 
which may be deposited there. 




egg-clusters 



Fig. 5. 
Pocket mirror. 



126 THE GYPSY MOTH. 

Mirrors are also useful in reflecting sunlight into the holes and 
cavities of trees and rocks, so as to determine whether or not 
the eggs are hidden within these recesses. Occasionally hol- 
lows in the under surfaces of high limbs are inspected from the 
ground by the combined use of the opera and hand glasses, 
the hand glass throwing the light into the hollow, and the 
opera glass enabling the inspector to determine its contents. 
During the spring of 1891 the egg-clusters, being then 
very numerous, were found in almost every conceivable 
situation. They were deposited on the under surface of 
steps, under piazzas, floors, beneath the baseboards offences, 
in hollow fence posts, in sheds, out-buildings, cisterns, con- 
ductors, ventilators, basements, cellars, chimneys and many 
other places both within and without dwellings. Their num- 
bers in many such places were so great that it was deemed 
unsafe to allow them to hatch, lest the caterpillars should 
prove very destructive before their ravages could be stayed. 

Boards were therefore removed 
from fences, steps and buildings, 
and this work required the use of 
such implements as crow-bars, 
pinch-bars and hammers. Dark 
lanterns were frequently required 
fig. e. cleaning knives. j n ce rj arSj under piazzas and in 

barns. Special knives with blades bent at different angles 
were made for removing the eggs from the recesses of fences 
and trees. With the aid of such implements most of the 
hidden eggs were found and destroyed. 

The Destruction of Caterpillars. 
When the larvse first emerge from the eggs, they usually 
remain for several hours on the outside of the egg-cluster, 
or if the weather becomes cold or stormy, for two or three 
days. While in this position they may be quickly destroyed 
by the flame of a naphtha burner or by an application of 
creosote or kerosene. 

Banding Trees. 
After the eggs on trees have been destroyed, the young 
caterpillars which hatch elsewhere may be kept from ascend- 



BANDING TREES. 127 

ing the trees by encircling the trunks with some appliance 
or substance which the larvae cannot cross.* The protection 
of large trees by banding is most important as their size 
favors the distribution of the moth, rendering it both diffi- 
cult and expensive to care for them. 

Such trees are often situated near buildings, lumber piles, 
ledges, accumulations of loose rock or other objects which 
offer many hiding places to the caterpillars and other forms 
of the gypsy moth. Occasionally sheds or hencoops are 
built about the trunks of trees. When such places of shelter 
as are not readily accessible to the workmen are thus offered 
to the moth, the caterpillars must be prevented from ascend- 
ing the trees, and either destroyed by starvation or driven 
to other quarters. Where there is no other vegetation near, 
this may be accomplished by banding the trees in the early 
spring. If there is no other food in the vicinity, the young 
caterpillars prevented from ascending the trees will starve. 
If there are other trees within crawling distance which are 
so located and environed as to have no shelter about them 
inaccessible to man, the migration of the caterpillars thither 
will facilitate their destruction by the workmen. In wood- 
lands, if the eggs upon the trees are destroyed and the trees 
well banded previous to the hatching of eggs, which may have 
been overlooked on the ground, and all vegetation on the 
ground is killed by means of the cyclone burner soon after 
the caterpillars appear, extermination will result. The 
method of burning caterpillars in infested brush is shown 
in Plate XX. 

Bands are most useful for these purposes when put on just 
before the young caterpillars appear. They will then be 
fresh and sticky when the young larvae are weak and unable 
to crawl far if deprived of the sustaining and strengthening 
nourishment which they eagerly seek. Before the hatching 
of the eggs in 1891 and 1892 many of the large street trees 
in Maiden and Medford and some in Somerville were banded 
with strips of tarred paper. This work was first undertaken 
in Medford. It was proposed by the selectmen of that town 
as a means of protecting the trees from the gypsy moth and 

* In 1891 bands of loose cotton batting were experimented with for this purpose, 
but they did not prevent the larger caterpillars from ascending the trees. 



128 



THE GYPSY MOTH. 



the canker-worm, and a part of the expense was borne by 
the town. The bark of the tree was first scraped or planed 
at a height of about six feet from the ground, so that a 
reasonably smooth surface about six inches wide was formed 
extending around the trunk. A band of cotton waste was 
then placed on the smooth surface about the trunk, and a 
band of tarred paper about the cotton. A cord about the 
paper drew it closely to the cotton waste, which was thus 
pressed firmly against the tree. This waste was placed 
beneath the paper to prevent the newly hatched caterpillars 
(which can pass through very minute crevices) from crawling 
under it and so on up the tree. The tarred 
paper was then covered with a mixture con- 
sisting of three parts tree ink, one part pine 
tar and one part petroleum (residuum oil) . 
The cotton waste prevented this mixture 
from penetrating to the bark of the tree. 
Fig. 7 shows the band about the tree with 
the string removed and a piece torn away 
to show the cotton packing. The black 
band represents that part of the paper 
which was covered with the mixture. 
Tacks and staples were used where necessary to draw the 
paper and string closely to the tree. 

It was necessary at first to apply several coats of the mixt- 
ure, so that the tarred paper might become so well saturated 
that it would not absorb subsequent applications. When 
this was effected, an application was made at least twice a 
week for the rest of the season where trees on dusty streets 
were banded, but it was not required so often (except in very 
hot, dry weather) in orchards or woodland. As a result of 
the banding, most of the caterpillars were kept out of trees 
along the streets, and therefore there was little danger of 
their being distributed along the highways in such numbers 
as in former years. In badly infested localities this method 
cau only be effective when the eggs on the trees have been 
destroyed and a large part of the egg-clusters in the vicinity 
gathered. Otherwise, the massing caterpillars will bridge 
the tarred paper with their bodies and on this bridge others 
will cross, or else the young caterpillars will be borne on the 




Fia. 7. 



Tarred paper 
band. 



THE USE OF INSECT LIME. 129 

wind from the branches of one tree to those of another, ren- 
dering all precautions useless. 

In banding, all poles, dead trees and other objects which 
in any way communicate with banded trees must be removed 
or banded. Where the limbs of trees touch houses, fences, 
rocks or the earth, they must be so trimmed as to prevent 
such contact. Unless all such means of communication are 
cut otf, banding will not produce the desired effect. Much 
discrimination must be used in banding trees in cultivated 
lands, lest the caterpillars be driven from trees and scattered 
abroad among shrubbery, weeds or garden crops, where they 
cannot be so readily dealt with. 

Raupenleim Bands. 

In 1891 Mr. B. F. Fernow, chief of the Division of For- 
restry of the United States Department of Agriculture, 
recommended that "raupenleim" or "insect lime," a Ger- 
man preparation for the protection of trees, be used in this 
work.* A sample was ordered, but it arrived too late in 
the season to be experimented with that year. In 1892 
experiments were made, and later thirteen and one-half tons 
of the "leim" were ordered and used in banding 40,704 
trees during that season and the next. The raupenleim used 
in 1892 was very effectual, but much of the importation of 
1893 was apparently inferior in quality to that used the 
previous year, and the results obtained were anything but 
gratifying. If results similar to those of 1892 can be secured, 
this material will be of great value for use in this country 
against such insects as the canker-worms, which pupate in 
the ground and whose female imagoes are wingless. 

Raupenleim was used in the gypsy-moth work to take the 
place of the tarred paper bands. The advantages obtained 
from its use are that when of a good quality and properly 
placed upon the tree, it will remain soft and viscid for several 
months, and during that time will prevent the ascent of 
nearly all larvae and also wingless female imagoes. The sub- 

* Raupenleim, translated literally, would read " caterpillar glue." According to 
Webster, lime (a viscous substance) is akin to the German word "leim." It is 
used here in connection with the word insect in much the same sense as it is used 
in connection with bird as "bird-lime." 



130 THE GYPSY MOTH. 

stance has been used abroad, especially in Germany, for 
several years past. The government forestry authorities of 
Bavaria employ it to prevent the ascent of the nun moth. 
This insect in 1890 devastated the German forests to such 
an extent that ' * three thousand men were employed to check 
its ravages, and in one instance it was necessary to cut and 
burn a strip of timber four miles broad by five miles long to 
prevent further devastation." * 

It was ascertained by experiment that the application of 
this insect lime did not injure the trees, nor has any injury 
been observed to trees where it has been used in this country. 
Though the death of three or four young trees has been 
reported and credited to the injury caused by liming, it is 
possible that the primary injury was caused by too deep scrap- 
ing of the bark. In such a case the oil contained in the lime 
might penetrate the liber and cambium of the inner bark and 
eventually destroy the life of the tree. There is no necessity 
for scraping a smooth-barked tree. Though over 40,000 
trees have been banded in the work in Massachusetts, these 
are the only cases where injury is believed to have resulted. 
This agrees with the experience of the foresters in Ger- 
many, f 



* Dr. R. Hartig in " Forstlich — naturwissenchaftliche Zeitschrift," January, 
1892. 

t " The excellent results of the lime-rings for the prevention of larva? ascending 
the stem and feeding on the foliage of our forest trees has been proven during the 
past ten years. Not content with this, however, — for it became our duty to see if 
the lime itself did not injure the tree, — we examined the different layers of the bark, 
and can confidently assert that no harm to the most tender trees has been done by 
liming them. 

" We firmly believe that the man who scrapes the bark off the trees can do more 
harm in one hour than he could by ringing trees with lime the rest of the year ; and 
we would therefore recommend for the work, men who know the difference between 
the inner and outer bark of trees infested, and especially warn them to be careful of 
smooth-barked trees, from which they have to remove only such mosses and lichens 
as are found on them. On the trees — Dr. R. Hartig says — that were limed twenty- 
five years ago no bad results have been observed. In fact, on the part of the tree 
where the ring was laid on, the growth of wood was larger than either above or below, 
which he ascribes to the action of the lime on the outer bark, softening it somewhat 
and giving freer circulation of the sap in the inner bark. 

" Only in instances where the bark was scraped to the quick has the lime pene- 
trated, and therefore all harm must be ascribed to the scraping knife and not to the 
lime. 

" There is, therefore, no occasion for alarm as regards the ringing of trees with 
insect lime to preserve them from the ravages of insects of all kinds." — (Translated 
from "Forstlich — naturwissenchaftliche Zeitschrift," July 7, 1892.) 



LIME MACHINES. 



131 




A variety of machines have been devised in Europe for 
applying raupenleim to the trees. One of these, the " Eich- 
horn machine" (Fig. 8*), was imported by the Board and 
was used to some extent. It 
consists of a triangular wooden 
box with two handles, one of 
which is hinged and acts as a 
lever. At the apex of the box 
is an aperture of the size de- 
sired for applying the lime to 
the trunk of the tree. This 
receptacle being first filled 
with lime, a handle is grasped 
in each hand of the workman, Fig. 8. The Eichhom machine. 

who, by pressure brought to bear on both handles, forces the 
contents through the opening. In the mean time the machine 
is passed around the trunk, and a band of lime adheres to 
the bark. This machine can be used to advantage where the 
rings are put on at a height of three or four feet from the 
ground ; but where it is necessary to place them at a height 
of six feet or more, as on street trees, great strength is 
required to force the lime out, and the use of the machine is 
not practicable. In the machine as imported the aperture 
through which the lime passed was about one-fourth of an 
inch in width and one and one-half inches in length. It was 
found by experiment that the lime remained viscid for a 
longer time and was more effective in stopping the ascent of 
the gypsy-moth caterpillars if the band was made wider than 
the length of this opening, and of greatest thickness on the 
lower edge ; consequently the opening of each machine was 
enlarged to such dimensions as to deposit a band on the tree 
about one-half inch in thickness on the lower edge and two 
and one-half inches in width. The lime could be so put on 
by trowels or spades made for the purpose that the lower 
edge of the band projected more than half an inch from the 
bark. If this lower edge was made even thicker than this, 
and shaped at an acute angle, the oil, which gradually tried 
out from the surface of the band when exposed to the sun- 



* See also the single-handed Eichhorn machine, Plate XXII., Fig. 4. 



132 THE GYPSY MOTH. 

light, would trickle down to the edge and hang there, form- 
ing an impassable obstacle to the caterpillars. The intent 
of the lime bands used in the work on the gypsy moth was 
to prevent any caterpillars from ascending the trees. If a 
few reached the branches and remained in the trees, passed 
through their transformations and laid their eggs, it is obvious 
that the bands would be worthless for the purpose for which 
they were intended, though even then they might be useful 
in controlling certain other caterpillars which frequently 
spin or drop to the ground, as they would prevent most of 
them from reascending the tree. But in a case where exter- 
mination is sought, and destruction of all gypsy caterpillars 
is a consequent necessity, it is imperative to prevent their 
ascending large trees. Quite frequently the bands were 
injured or displaced in some way by people or animals 
brushing against them, and often leaves or twigs from the 
trees dropped and stuck upon the bands, forming bridges over 
which the caterpillars could climb. To' lessen the chances of 
their reaching the branches, two or even three bands were 
sometimes put upon the same trunk, one above the other.* 
The same thing has been done in Germany during great 
invasions of the nun moth (Liparis monacha), and for this 
purpose a machine has been devised for applying insect lime 
at a greater height on trees than could be otherwise reached 
by hand from the ground. 

The Hochleim machine (Plate XXL, Fig. l)f is a tin 
cylinder attached to a long pole. A top that acts as a plunger 
is fitted to the cylinder and may be depressed by pulling on 
a cord that is fastened to a strong spiral spring. This spring 
is connected with iron wires which are attached to the upper 
part of the machine. When this is depressed, the lime is 
forced out at the bottom of the machine through a round hole 
bored in a brush which is fastened to one side, as seen in the 
figure. The lime, which must necessarily be of a more or 
less liquid consistency, is applied around the trunk of the 



* This would not be ordinarily necessary in protecting trees against attacks of 
native caterpillars. 

f Figures of the implements and machines appearing on plates XXI. and XXII. 
have been previously published, together with others, in "Die Nonne," by Dr. H. 
Nitsche, Ed. Holzel's Verlag, Vienna, 1892. 



PLATE XXI. 




PLATE XXII. 





Fig. 3 




o 




LIME MACHINES. 133 

tree with the brush. The tools (Plate XXL, Fig. 2, a, b, c) 
are also attached to poles, and are used for scraping and 
smoothing the bark at a height. Tool c has a scraper upon 
one side and a stiff brush upon the other. The lime hose 
(Plate XXL, Fig. 4) is an elongated cone-shaped bag made 
from some thick fabric. It has a mouth-piece at the small end 
for the outlet of the lime, while on the large end is attached 
a tin ring or cover, by means of which the bag may be filled 
and closed. This apparatus is carried by a strap or band 
passing over the right shoulder, and the lime is squeezed out 
by forward pressure of the right hand. It is inexpensive, 
easily carried and durable ; still, it cannot be entirely satis- 
factory, as the oil with which the lime is mixed will gradually 
work through the fabric and soil the clothing of the workman. 

The Eck lime hose is illustrated also (Plate XXL, Fig. 5), 
but, as the filling is done at the smaller end, requiring an 
expensive apparatus for forcing the lime in, it would hardly 
seem a desirable machine, although its cost in Germany m 
small (1 mark, about 25 cents). A very simple machine is 
a large tin cylinder (Plate XXL, Fig. 6) with a piston, the 
handle of which is pushed in by the man using it, who in 
this way drives the lime through the tin mouth-piece. This 
mouth-piece can be removed and others of different sizes can 
be substituted, according to the thickness and shape of the 
lime ring desired. 

The Seitz lime machine (Plate XXII. , Fig. 2) is a large tin 
apparatus holding about two and one-half quarts. The cover 
is fastened with a "bayonet" lock. The piston, which is 
geared, is worked back and forth by a geared wheel or cog 
fastened to the cover, and turned by a handle. This larger ap- 
paratus, rather heavy when filled, is carried crosswise in front 
of the workman, who turns the handle with his riirht hand. 

The Hauenstein lime machine (Plate XXII. , Fig. 3) is 
operated on the same principle as the last, except that the 
piston is driven forward by spring-power. The tin mouth- 
piece is connected with the main body of the machine by a 
piece of hemp hose, which is movable. The spring is drawn 
by the aid of a wire rope with a loop at its end. The work- 
man sets his foot in the loop, draws the machine upward and 
so draws the spring, which is arrested by a snap latch. The 



134 THE GYPSY MOTH. 

machine is then filled. When in use the spring is released 
from the latch. Like the other machines, this machine is 
carried by a harness or carrying band. 

A simple utensil (Plate XXII., Fig. 1) is like the "Eich- 
horn" machine, a lime " squeezer," and consists of a wedge- 
shaped box, one side of which is movable and may be pressed 
into the opening formed by the four stationary walls of its 
other sides. Spades or trowels (Plate XXI., Fig. 3, a, b, c) 
are often used to apply the lime and shape the bands where 
the work is done by hand. Where a number of men are at 
work, a lime hod (Plate XXII., Fig. 5) is also used. This 
hod is carried by one man, who keeps several others supplied 
with the lime. 

There are some disadvantages in the use of insect lime. 
It is not cleanly, as under a hot sun more or less running oil 
exudes, especially on smooth-barked trees. Unless placed 
at a considerable height from the ground, cattle and horses 
frequently rub against it, plastering their coats in a very 
disagreeable manner. Complaints have been occasionally 
received that pet cats returning from excursions up the tree 
trunks have "tracked" the insect lime over their owners' 
carpets. Notwithstanding all care that has been used in the 
application of the material, certain spring overcoats and fine 
shawls have been ruined when the owners of these garments 
carelessly leaned against trees which had been banded. The 
insect lime does not adhere well to trees when they are wet, 
and occasionally heavy showers will cause it to drop off in 
lumps. These lumps when trod upon adhere to the shoes 
and are sometimes a source of considerable annoyance to 
housekeepers. Such accidents may be avoided by applying 
the lime when the trees are dry, and by forming the band 
with its upper edge bevelled toward the tree so as to shed 
water. It is then not likely to be displaced by rains. 

If the lime is used on trees standing on lawns, it is likely 
to prove a source of unpleasantness. Some complaints in 
regard to this have been received from owners of lawns and 
croquet grounds. Such objections to its use will apply, how- 
ever, to any material of the kind, and are not to be avoided 
as the lime is ordinarily used. It is sometimes recommended 
to place a band of stiff paper about the tree, turn up the 



LIME AND DENDROLENE. 135 

lower edge in such a way as to form a trough and then apply 
the lime upon this. If this band of paper is placed at a 
considerable height, it may prevent many of the disagreeable 
accidents which otherwise frequently happen. Thus far we 
have had no experience in applying the lime in this manner. 

Other Uses, for Insect Lime. 
Dr. John B. Smith, entomologist of the New Jersey Ex- 
periment Station, in a paper read by him as president of the 
Association of Official Economic Entomologists at a meet- 
ing of that society held Aug. 27, 1895, in connection with 
the meeting at Springfield of the American Association 
for the Advancement of Science, gave the results of his 
experiments with raupenleim and a similar material, "den- 
drolene."* Dendrolene was invented by Prof. F. L. Nason 
of New Brunswick, who, at the request of Dr. Smith, experi- 
mented with a view of obtaining a material of home manu- 
facture possessing the insecticide and protective properties 
of the raupenleim. According to Dr. Smith, raupenleim and 
dendrolene are both crude petroleum products, though the 
raupenleim has some admixture of a substance resembling tar 
in color and odor ; but in both cases the base is, or seems to 
be, a very crude or impure vaseline, which has the appearance 
of the base of such lubricating mixtures as wheel-grease. 
Dr. Smith has used both substances on trees to prevent 
both the entrance and the emergence of certain tree borers. 
So far he has seen no injury to the tree resulting from the 
use of either material, even when large areas of bark were 
covered. While the raupenleim seemed more effective 
against borers, the dendrolene remained soft longer, making, 
as Dr. Smith says, "a perfect barrier against insects 
attempting to cross it." He also says that " such materials 
may be employed against scale insects on comparatively 
small trees where they cover only the trunks and larger 
branches, and where even a thin coating applied with a brush 
early in the season before the eggs have hatched or before 
reproduction has begun in the case of the viviparous species, 
will absolutely prevent the emergence of young. The appli- 

* See Bulletin of Experiment Station, New Jersey Agricultural College, No. Ill, 
Sept. 16, 1895. 



136 THE GYPSY MOTH. 

cation of a coating on the trunks of peach trees made early 
in the season will prevent oviposition by the adult of the 
peach tree borer." But it may be questioned how far this 
covering; the bark with such a material can be carried with- 
out eventually injuring the tree. Our experiments go to 
prove that raupenleim will usually prevent the ascent of 
the female canker-worm moth. It is quite probable, however, 
that after wet or cold weather, some of the moths may cross 
the band before the warmth of the sun has rendered it viscid, 
as the lime hardens somewhat in such weather and does not 
again become soft until affected by the sun's warmth. 
Climbing cutworms and many other caterpillars have been 
caught on the bands. Most insects, however, seem to prefer 
to turn back rather than attempt to cross. The larger gypsy- 
moth caterpillars will cross when the bands have become 
somewhat hardened by rain or cool weather, but the smaller 
caterpillars seldom crawl over the bands. The raupenleim 
was therefore very useful for banding trees which had been 
cleared of the moth, providing the young caterpillars could 
be destroyed by fire or other means before they attained 
sufficient size and strength to cross the lime. The bands are 
useful also in preventing the ascent of such common pests 
as the tent caterpillar and tussock moth after trees have been 
cleared of the caterpillars or eggs of these species. * Dr. Smith 
says that as a protection against mice and hares, "dendro- 
lene will serve an entire season when put on one-fourth of an 
inch thick or more." As much cannot be said of the raupen- 



* The application of bands of insect lime appears to prevent the common tent 
caterpillars from crawling either up or dewn trees. A wild cherry tree which con- 
tained a great number of these caterpillars was banded with insect lime. When the 
caterpillars had devoured all the foliage upon the tree they crawled down the trunk 
to the band and there remained clustering upon the trunk within two feet of the 
upper edge of the band, where they died, apparently of starvation. This would 
indicate that by banding worthless trees infested by this insect it might be prevented 
from migrating to other trees, and compelled to perish from lack of suitable food. Yet 
no instance of this kind has been observed with any other insect, and no record was 
kept of the number of caterpillars originally on the tree, so it is impossible to tell 
how many may have escaped. It is not safe to base any conclusions on a single 
observation of this sort. It is given here merely to show the necessity of further 
observation and experiment with insect lime, which can probably be used in many 
ways as a preventive to insect attacks or an insecticide application. 

The application of the insect lime to egg-clusters has already been mentioned 
(page 125) , but it has been superseded in Massachusetts by more economical and 
effective measures (page 123). 



SPRAYING. 137 

leini used for the gypsy-moth work, although the best of it 
remained in good condition from one to three months ; yet 
in some cases it became necessary to make two or three ap- 
plications during a season. During windy weather bands 
upon dusty streets require frequent attention and occasional 
renewal. Dr. Smith says that in no case has he ever ob- 
served any injurious effect of dendrolene upon the trees. 

Dendrolene is supplied by Prof. F. L. Nason, New Bruns- 
wick, N. J. Insect lime can be obtained of the Bowker 
Fertilizer Company, Boston, Mass., and of Wm. Menzel & 
Son, New York. 

/Spraying with Paris Green. 
When the second commission began work in the spring 
of 1891, it was learned that the efficacy of Paris green as an 
insecticide for the gypsy moth was doubted by many people 
in Medford. Experiments were therefore immediately begun 
to determine whether spraying with Paris green would kill 
the caterpillars. In April young caterpillars were hatched 
by artificial means in the office of the commission and fed 
upon leaves which had been carefully sprayed with a solution 
consisting of one pound of Paris green to one hundred and 
fifty gallons of water. Not only was the ordinary Paris 
green experimented with, but samples of finely bolted poison 
were secured. The experiments showed that the use of 
either quality of Paris green caused death. It was noticed, 
however, that the caterpillars which ate the leaves sprayed 
with the pulverized poison died soon after beginning to feed, 
or within twenty-four hours ; while those which ate of the 
leaves sprayed with the ordinary Paris green lived for several 
days, very few dying within twenty-four hours. The ma- 
jority lived three or four days and some even a longer 
time. Samples of both the pulverized and ordinary Paris 
green were analyzed and the analyses gave substantially the 
same amount of arsenic in each. From this it would appear 
that both were equally poisonous. Why they were not 
equally effective has not been fully determined. But as the 
ordinary Paris green was made up of fine crystals which were 
more or less insoluble, while a larger proportion of the finely 
powdered Paris green was apparently soluble in water, the 



138 THE GYPSY MOTH. 

latter would be more quickly dissolved in the digestive 
fluids of the caterpillars. This subject, however, needs 
more scientific investigation, as the experiments made were 
too limited in scope to allow any conclusions to be based 
on the results. As it was found later that neither brand 
of Paris green gave as satisfactory results in the field as 
had been obtained in-doors, and as the use of this arsenite 
was finally given up, the subject of the comparative efficiency 
of the pulverized and the ordinary Paris green was not 
further investigated. 

The results obtained by in-door experiments with the pul- 
verized Paris green led to experiments on a larger scale in 
the field and accordingly a ton of this poison was purchased. 
Early in May spraying in the field was begun (see page 55). 
Most of the sprayers were supplied with the fine Paris green, 
which, though not proving as efficacious as in the laboratory, 
nevertheless killed many of the smaller caterpillars. As the 
spraying continued it was observed that a considerable pro- 
portion of the caterpillars of middle age were also destroyed. 
Sometimes, though rarely, persistent spraying appeared to 
destroy most of the larger caterpillars. By this time it had 
been determined by experiments in the laboratory that Paris 
green would not kill all the larger larvae ; yet as it had 
given better results than any other insecticide, it was thought 
best to continue its use at varying proportions in the field, 
and the poison was used at a strength of from one to four 
pounds to one hundred and fifty gallons of water. As a 
rule the spraying did not seriously burn the foliage when a 
solution was used consisting of one pound of Paris green to 
one hundred and fifty gallons of water; but with larger 
proportions of poison the foliage was considerably burned. 
The injury developed so rapidly that within a short time the 
leaves were all killed and the surviving larvae were obliged to 
go elsewhere to feed. Therefore, a strong Paris green mixt- 
ure had little better effect than a weak one. Lime was 
then used with the Paris green with a view of neutralizing 
the burning but considerable injury to the foliage still con- 
tinued. 

Though even when three or four pounds of the Paris green 
were used to a tank of water, many of the larger feeding 



EFFECTS OF SPRAYING. 139 

caterpillars survived. Yet a difference in the effect of the 
spraying on the caterpillars was noticed. Occasionally in 
badly infested places so many of the caterpillars died within 
two or three days after the spraying that the people living 
on the infested estates were obliged for the sake of cleanliness 
to sweep up the dead from the walks and burn them. The 
unevenness in the effect of the spraying at once aroused 
suspicion that it might be caused by improper mixing or 
application of the insecticide. Although some inefficiency 
on the part of inexperienced sprayers was expected, a great 
difference in the effect of the insecticide was observed even 
when the poison was most thoroughly and carefully mixed 
and uniformly applied. 

Every effort was made during the spraying season to de- 
termine why the results of spraying were not uniform and 
satisfactory. The feeding caterpillars were watched day and 
night by many observers. The spraying was most carefully 
superintended and the conclusion finally arrived at was that 
under ordinary conditions spraying with Paris green for the 
gypsy moth was ineffective and unsatisfactory.* 

* In a few cases, where spraying was done just after a storm, an unusual mortality 
among the caterpillars was noticed during the next few days. At first it was thought 
that this result was due to the poison being more effective at such times, on account 
of its better retention on the foliage. It was known, also, that the caterpillars sought 
shelter and ate but little during rains, but that they fed ravenously during the warm, 
clear weather that frequently follows a storm. It was believed that the unusual 
amount of poisoned food taken at such a time, when the system was weakened by 
fasting, might have been sufficient to cause a greater mortality than usual. It was 
soon noted that the poison appeared to produce the same effect occasionally in dry 
weather or after light rains. This seemed to disprove the first hypothesis advanced, 
and raised the question whether the larvas, which sometimes succumbed in such 
numbers, were not first weakened by disease or other causes. 

In some cases the accuracy of the observations was doubted. It is difficult to make 
accurate observations on the results of such work done in the field. For instance, 
it is almost impossible to determine the proportion of larvte killed by spraying. 
When they disappear immediately after spraying, there is no certainty as to whether 
the spraying alone is responsible for their disappearance, or whether they have not 
been carried off by birds or predaceous insects, or have not crawled to other localities 
or to more congenial food. In some places, where the dead larvae fell to the ground 
in considerable numbers, most of them were immediately carried away by ants or 
other scavengers, which left few behind to tell of the results of the spraying. Cor- 
rect conclusions cannot be drawn where there is such liability of error, unless obser- 
vations recorded by many careful individuals and extending over a considerable 
period of time agree in the main. As no extended spraying with Paris green was 
done after 1891, the opportunity passed for an exhaustive study of the effect of 
meteorological or other conditions on the results of spraying. The cause of the 
apparent differences in the results of carefully conducted spraying with Paris green 
for the gypsy moth is a question which deserves further investigation. 



140 THE GYPSY MOTH. 

It is interesting to note that while many of the gypsy 
caterpillars were apparently uninjured by the spraying, the 
canker-worms and tent caterpillars were almost exterminated, 
and the tussock moths (Orgyia leucostigma) disappeared. 
The trees of the infested region were never in better con- 
dition than at the end of the spraying season of 1891, and 
the fruit crop was larger than it had been for many years. 
Though this cannot all be credited to the spraying, the con- 
trast between sprayed and unsprayed trees was often very 
marked, the sprayed trees bearing more and finer fruit. 

During the spraying season thirty heavy spraying outfits 
were worked back and forth between the outer part of the 
infested region and its centre. Fifteen towns were thus 
covered. There were also a dozen light fifteen-gallon hand 
tanks which were sent into the outer towns. They were 
carried in wagons, two men being assigned to each wagon. 
The tanks and pumps used were the same as are used with 
the cyclone burner (Fig. 1, page 120). The men with the 
light outfits went to the outlying orchards and residences, 
where a few trees were infested. They filled their tanks at 
brooks or wells and carried them by hand to such infested 
spots as were not accessible by a team, sprayed the trees in the 
vicinity, reloaded the tanks upon the wagons and drove to the 
next infested place. In this way the isolated colonies in the 
outer towns were covered by the sprayers. The large tanks 
mounted upon wagons and handled by from four to six men 
were used mainly in towns where water service was available 
and were filled from hydrants or stand-pipes. The order was 
given to spray everything green within two hundred feet of an 
infested plant or tree. An adherence to this regulation caused 
the spraying of all vegetation in the worst infested towns. 

No extended spraying with Paris green has been done since 
1891. While spraying with Paris green cannot be considered 
a successful method of extermination, it destroyed a consid- 
erable proportion of the number of very young caterpillars 
wherever it was done efficiently and in season. It thus 
checked the multiplication and assisted in preventing the 
spreading of the species. Though it failed to accomplish 
the end sought, it was certainly the most effectual method 
known at that time of disposing of the young caterpillars. 



LONDON PURPLE. 141 

In looking back over an experience of five years we are 
unable to see how any better method of destroying the young 
larvae could have been devised from the knowledge of in- 
secticides then possessed. 

Spraying loith London Purple. 
London purple was used both in-doors and in the field in 
the season of 1891 but the results of the experiments with it 
were not as satisfactory as those reached with Paris green. 
While it was quite as effective as Paris green in destroying 
larvae, it injured the foliage more. London purple is more 
finely powdered and lighter than Paris green and requires 
less stirring. It also has the advantage of cheapness. The 
great objections to its use are its partial solubility in water, 
which causes burning of the leaves, and the unevenness of 
the effects produced by it. While one sample may give fairly 
satisfactory results, the next may not only burn the foliage 
badly but even the young fruit on fruit trees. According to 
Professor Bailey the arsenic in London purple is in the form 
of arsenite of calcium, which in some samples is about seventy- 
two per cent, of the whole compound. Over fifty per cent, of 
this arsenite or nearly forty per cent, of the London purple is 
quickly soluble in water. * The analysis of leaves injured by 
Paris green shows no arsenic in the texture of the leaf; but 
when leaves injured by London purple are analyzed, arsenic 
is found in their texture. This shows the penetrative powers 
of the latter poison. The London purple was used in the 
field to some extent, but the conclusion arrived at was that 
while, as it is ordinarily used, one might be justified in ex- 
perimenting with it upon his own premises, its use in public 
work on the premises of others was unwarrantable. 

Spraying with Arsenate of Lead. 
Although nearly all poisons known to us which can be 
used as insecticides have been experimented with during the 
past five years in the hope that something would be found 
which would prove fatal to the gypsy moth, only one which 
is more effective than Paris green has been discovered. This 

* See "Experiences in Spraying Plants" by Prof. L. H.Bailey, Report Agricultural 
Experiment Station, Ithaca, N. Y., Bulletin 18, 1890. page 98. 



142 THE GYPSY MOTH. 

is arsenate of lead, a poison slower in its action than the 
other, but which has three distinct advantages: (1) It can 
be used at any desired strength without serious injury to 
the foliage; (2) It is visible wherever used, as it forms 
a whitish coating on the leaves ; (3) It has adhesive quali- 
ties, given it, probably, by the acetate of lead, and therefore 
remains on the leaves for a much longer period than Paris 
green. When sufficient glucose was added to a strong mixt- 
ure of arsenate of lead, it withstood rainstorms and remained 
on the foliage during an entire season. 

When in 1891 it became evident that the arsenites would 
not accomplish the desired result, other means of destroying 
dispar were sought. Yet it could be hardly credited that 
the larva was indifferent to the action of arsenical poisons as 
ordinarily used, and the experiments of 1891 were duplicated 
during the season of 1892. They were performed by Pro- 
fessor Fernald and his assistants, but the results of these 
experiments confirmed those of 1891. 

When it was seen that the known arsenites could not be 
used at the requisite strength for killing gypsy-moth cater- 
pillars without serious injury to the foliage, Mr. F. C. 
Moulton, one of the inspectors employed in the field, who 
was also a chemist graduated from the State College of Agri- 
culture and Mechanic Arts, Orono, Me., was detailed to make 
experiments to determine what portion of the compound 
produced the caustic effect upon the foliage. The results 
of the experiments confirmed the conclusions of previous 
experimenters that the soluble arsenic burned the foliage. It 
was obvious that if a form of arsenic entirely and quickly 
soluble in water could be precipitated, it would become 
insoluble and obviate the burning. 

In the winter of 1892-93, at a hearing before the legis- 
lative joint standing committee on agriculture, a bill for the 
destruction of caterpillars within the State was considered. 
At this hearing Mr. Andrew H. Ward proposed the use of 
arsenate of soda as an insecticide. At the hearing we ob- 
tained from Mr. Ward the particulars in regard to the price 
of arsenate of soda and where it could be procured. 

Upon consultation with Professor Fernald (who had also 
been previously asked by Mr. Ward to try the insecticide 



ARSENATE OF LEAD. 143 

properties of arsenate of soda), he advised experimenting 
with it. A sample was procured and was found to be entirely 
soluble in water. When used it burned the foliage to a 
greater extent than the other arsenical poisons. Mr. Moul- 
ton was detailed to find some material which would precipi- 
tate the arsenate of soda in water and thus obviate the 
burning. He proposed acetate of lead and after several 
experiments the desired result was obtained and the pro- 
portions were fixed. The effect of the mixture of acetate 
of lead with arsenate of soda in water is to throw down the 
arsenate of lead in a fine precipitate which is held well in 
suspension by the water and is therefore more evenly dis- 
tributed than Paris green. 

While the complete insolubility of arsenate of lead is an 
advantage as far as its effects on the plants are concerned, 
it is less effective on the insect than Paris green when used 
in equal quantities. Though the action of arsenate of lead 
is slower than that of Paris green and London purple, this 
may be partially accounted for by the smaller proportion 
of arsenic in the composition. Caterpillars poisoned with 
arsenate of lead have quite a different appearance from those 
poisoned with Paris green. Inflammation and the shedding 
of hair appear to be symptoms of poisoning by arsenate of 
lead. As it is slow in its action, it is well to apply it early 
in the life of the caterpillar or in great strength. 

The experience with arsenate of lead is in some respects 
analogous to that with Paris green. While in-doors there is 
no difficulty in destroying caterpillars with small quantities 
of the poison, the effects obtained out-doors are not so satis- 
factory. Indeed, it is only when applied at a strength of from 
twenty-five to thirty pounds to one hundred and fifty gallons 
of water that it appears to do exterminative work. This, to 
some extent, may be due to the difference in the material. 
The arsenate of lead used in the laboratory was furnished in 
the form of a fine dry precipitate. In the field the two 
poisons were furnished in a cruder state. They were added 
to the water and precipitation took place in the tank. The 
preparation was much less expensive when made in this 
way but was not as finely powdered. Indeed, it required 
considerable stirring in warm or hot water to dissolve the 



144 THE GYPSY MOTH. 

lead sufficiently for it to pass through the strainers of the 
pump. When arsenate of lead has been applied in pro- 
portions of from twenty-five to thirty pounds to one hun- 
dred and fifty gallons of water, occasional burning has been 
noticed. This was due to the fact that the lead was not 
thoroughly dissolved, for in such cases there was a lack 
instead of an excess of acetate of lead in the mixture as it 
came from the nozzle. When applied in this strength it 
is a question whether it is safe to use it in pastures where 
cattle are feeding or near where poultry are quartered. 

It is evident that spraying with arsenate of lead should be 
used as an exterminative method only in exceptional cases 
where there is no danger to animals and where more drastic 
measures, such as fire, cannot be used. While it will un- 
doubtedly be useful with many other insects, we would not 
recommend that implicit reliance be placed upon it unless 
used early in the season and at a strength of at least three 
pounds to one hundred and fifty gallons of water. However, 
it will probably not be necessary to use it at this strength 
for all leaf-eating insects though some may require a greater 
strength. Many experimenters have made trials of this ma- 
terial since the formula was first published in the annual 
report of the State Board of Agriculture in 1894, but we 
are not aware that it has yet come into general use in practi- 
cal out-door work. Professor Fernald's experiments with 
arsenate of lead on the tent caterpillar indicate that it would 
be effective with this species in the field when used at a 
strength of one pound to one hundred and fifty gallons of 
water. It has given good results when used by him at the 
same strength for the Colorado potato beetle (Doryphora 
decemlineata, Say) . Larger quantities have been required for 
some other insects. 

At first sight it would seem that if it were necessary to use 
three pounds of arsenate of lead to one hundred and fifty 
gallons of water, the expense would be prohibitory. Yet it 
should be borne in mind that when mixed with glucose and 
properly applied to dry foliage, much of the solution will 
remain throughout most, or all, of the feeding season. Its 
application is not, therefore, as expensive as that of poisons 
which have to be applied three or more times during the season. 



SPRAYING APPARATUS. 



145 



By making a strong application early, the expense of the 
labor of making the later applications is done away with. 
Experiments being made by entomologists in different parts 
of the country will soon indicate the degree of usefulness 
of this arsenate in destroying different species of native and 
introduced leaf-eating insects. Practical use in the field 
later will determine its value as a general insecticide. 

In the field work of the Board of Agriculture the formula 
of arsenate of lead most used was sodic arsenate, 29.93 per 
cent., plumbic acetate, 70.07 per cent. Two quarts of glu- 
cose were generally added to 150 gallons of water to give 
better adhesive qualities. 

Professor Fernald directs that arsenate of lead can be 
prepared in the proportion of eleven ounces of acetate of lead 
and four ounces of arsenate of soda in water. 



Apparatus used for Spraying Large Shade and Forest Trees, 




Fig. 9. Spraying tank. 

The heavy spraying outfits used by the first commission 
in 1890 were again put in service by the State Board of 



146 THE GYPSY MOTH. 

Agriculture in 1891, but were so improved and modified by 
labor-saving attachments as to render them doubly effective. 
For each of these outfits a tank or hogshead holding one 
hundred and sixty gallons (Fig. 9) is provided, bearing on 
its upper end a plank foot-board six feet long and one foot 
wide. A double-acting Douglass or Gould force-pump (see 
Plate XXV., Fig. 1, and Plate XXVI., Fig. 2) is mounted 
near the middle of the foot-board. Either of these pumps 
when well manned furnishes sufficient force for all kinds of 
spraying with several nozzles at once. The suction pipe of 
the pump descends into the tank at the side and reaches to 
within two inches of the bottom, where it is terminated by a 
fine wire gauze strainer made from No. 32 wire, woven forty 
or fifty meshes to the inch, which serves to exclude all foreign 
substances which may clog the pump or nozzle. The diame- 
ter of the strainer should not be less than twice that of the 
suction pipe. In the head of the tank is inserted a stirrer 
made from two pieces of two-inch spruce scantling, one six 
feet and the other two feet in length, the two being joined at 
right angles at the lower end of the longer piece. When 
placed in the tank the long arm is hinged on a bolt or rod 
at the opening in the head of the hogshead while the short 
arm swings just clear of the bottom. This lever projects 
above the top of the tank. By moving it back and forth 
the liquid is thoroughly agitated. The pump is operated 
by means of a powerful lever or brake worked by one or 
two men, according to the amount of pressure needed. It 
is connected by means of a Y coupling with two lines of hose 
upon which from two to six nozzles can be used. The men 
when pumping stand on the foot-board already mentioned. 
The whole apparatus is lashed on a wagon or cart and trans- 
ported from place to place as required. When in use one 
man operates each line of hose, the driver of the team usu- 
ally does the stirring, while the whole work of spraying 
is directed by an inspector. With this apparatus there is 
no difficulty in spraying at any required height. Two 
men on the brakes furnish force sufficient to throw a good 
spray from a Gem nozzle when held ninety feet from the 
ground. 



SPRAYING APPARATUS. 147 

Thorough and constant stirring is the prime requisite for 
obtaining satisfactory and uniform results in spraying, as 
the arsenical compounds used do not enter into true solution 
with water, but having greater specific gravity remain in sus- 
pension only. For this reason the particles of the poison 
have a constant tendency to settle to the bottom of the tank. 
Therefore the strength of the solution varies according to 
the amount of agitation given it. Hence the necessity of 
a continuous stirring of the contents of the spraying tank 
even when the pump is not being used, as while it is 
being taken from one tree to another. Even with con- 
tinuous stirring the liquid issuing from the nozzle when 
the tank was nearly emptied usually contained more poison 
than that taken from a full tank or one half full. In most 
spraying machines the liquid is agitated only when the pump 
is in motion and the insecticide settles when the pump is 
not in use. It then becomes necessary to scrape the bottom 
of the tank and stir vigorously. 

Several kinds of hose were used in spraying. The half- 
inch, rubber-lined, cotton-covered Eureka howe was found to 
be most convenient for the heavy apparatus on account of 
its light weight. For light machines, where only one small 
nozzle is used to each line of hose, quarter-inch rubber tub- 
ing is large enough. Each spraying gang was supplied with 
eight pieces of hose, each fifty feet in length, which were 
used in two lines of two hundred feet each. These were 
sometimes united to form a single line so as to spray places 
which, from their locality, could not be reached otherwise. 
In general use, however, the two lines of hose were used 
simultaneously. A " shut off" was coupled on each line of 
hose near the pump and also at the nozzle. 

Not the least important part of the spraying apparatus is 
the nozzle. The desirable qualities of a nozzle for spraying 
large trees are that it shall throw voluminous jets of spray 
to a distance of eight or ten feet, clear itself readily, and 
be easily adjusted to varying distances, thus enabling the 
workmen to work rapidly. A series of tests was made with 
thirty-three different kinds of nozzles. The Lowell and Gem 
nozzles were found to be most effective. Both of these noz- 



148 THE GYPSY MOTH. 

zles are operated on the same principle and both have been 
much used in the gypsy-moth work. A good climber us- 
ing the Gem nozzle can spray large trees both thoroughly and 
rapidly. 

When it is impossible to reach the ends of branches with 
a fine spray, a turn of the nozzle will cause a heavier spray 
to be thrown to a distance of ten or twelve feet. If neces- 
sity requires, this can be reduced to a stream which can be 
forced upward for thirty feet, where it will break into drops ; 
but when the foliage can be reached with a spray, the use 
of the stream should not be permitted, as such work does 
not give the best results. 

There are some objections to the use of these nozzles. They 
waste more or less of the liquid and do not distribute it so 
finely as some other nozzles. They also may tempt the 
workman to avoid climbing by substituting the stream for the 
spray where the branches are not easily accessible, thus im- 
pairing the efficiency of the spraying. Yet if the operations 
are superintended by competent men, this may be guarded 
against and the work done far more rapidly than with non- 
adjustable nozzles throwing a finer spray. 

The Lowell nozzle (Plate XXIV., Fig. 2) consists essen- 
tially of two brass tubes placed one within the other. The 
inner tube at its posterior end bears a coupling by means of 
which it is connected with the hose, while the anterior end 
terminates in a tapering point at the base of which on op- 
posite sides are two openings which allow the fluid to escape 
into the chamber between the tubes. The cone-shaped point 
of the inner tube tapers for about two-thirds of its length, at 
which point its diameter is abruptly enlarged and then tapers 
again at an increased angle to its apex. On the outside of the 
inner tube is a coarse screw thread which moves on a blunt 
screw inserted through the side of the outer tube and by 
this arrangement the latter is moved forward and backward. 
This outer tube, which is slightly shorter than the inner one, 
closes on the latter at the posterior end by means of a band 
of packing held in place by a movable nut. At its anterior 
end it is widened to form a bell-shaped opening which at 
the centre closes tightly around the tapering point of the 
inner tube. When in use the outer tube is slid forward by 



Plate XXIV. 



4l§ ' 



"■-SSSr* 





Fig. I. 



Fig. 2. 




M2 I 








Fig. 3. 



Fig. 4. 



Plate XXV. 




Plate XXVI. 




Plate XXVIL 




Fig;. I. 



Ml' Mill 

Fig. 5. 





Fig. 4. 




Fig. 2. 




Fig. 3. 



Fiz. 6. 



SPKAYING APPARATUS. 149 

a rotary motion on the screw bearing of the inner tube, and 
the spraying solution is forced out through the circular space 
thus opened between the point of the inner tube and the 
inner surface of the outer tube, which surround it. By 
turning the outer tube the density of the spray and the dis- 
tance to which it can be thrown are regulated. 

The Gem nozzle (Plate XXIV., Fig. 4) is made on the 
same principle as the Lowell. In using these nozzles a strong 
pressure is required to insure a fine spray. 

For spraying orchard trees and shade trees of ordinary 
size, light hand ladders were found to be very serviceable. 
But when the tops of tall street elms were sprayed, extension 
ladders, thirty, forty or even sixty feet in length, were nec- 
essary. A heavy extension ladder sixty-five feet in length, 
such as is used by firemen, was purchased for the latter 
purpose. This ladder could be readily and skilfully handled 
by six men with the aid of blocks and tackle. The small 
hand ladders were carried on the spraying wagons and the 
larger ones by hand or upon wagons, hand-carts or wheels, 
as was most convenient. Ladders mounted permanently 
upon wheels could not be used to advantage on account of 
the uneven nature of the ground where much of the spraying 
was done. Ladders twenty to twenty-five feet in height with 
braces so made that they could be set up like step-ladders 
were used at first, but they were unwieldy and it was soon 
seen that more effective work could be done by using light 
ladders and climbing into the trees themselves. In climbing 
fruit and shade trees care must be taken not to injure the 
branches. 

Machinery for Spraying Orchard Trees and Garden Plants. 

Although in spraying small gardens and orchards any good 
tank or pump may be used, the heavy and more cumber- 
some outfits are not necessary. A small portable tank and 
pump which can be taken about by the operator, either 
attached to his person or upon a wheelbarrow, will suffice 
for all the spraying required in small estates. 

For spraying garden plants and small fruit trees the 
" knapsack pump," which is fastened on the shoulders, 
has been oiten recommended for use in small gardens and 



150 THE GYPSY MOTH. 

orchards. The Gould handy knapsack spraying pump 
(Plate XXIV., Fig. 1) has been used experimentally in 
the gypsy-moth work and gives fairly good results. These 
knapsack sprayers, however, are inconvenient when spraying 
is required on a large scale as they do not carry sufficient 
liquid. 

The hand tank and pump used with the cyclone burner 
(page 120, Fig. 1) has been found very useful in spraying 
small orchards. With the pole attachment most of the trees 
can be sprayed from the ground. This tank may be carried 
and operated by two men. 

Gould's barrel sprayer is shown in Plate XXV., Fig. 2. 
It has been very useful in our experimental work, and could 
no doubt be used to advantage in spraying small orchards, 
gardens and field crops. It has the advantage of being 
movable without the aid of a horse. Its wide tires can be 
run over ground where it would not be possible for a horse 
to go without doing injury. 

In spraying in gardens where tender and valuable plants 
are grown or in orchards containing choice varieties of fruit 
trees, it is most essential that the liquid be thoroughly 
stirred, and especially that the spray be distributed evenly 
and in a fine mist, otherwise injury to the plant may result. 
Spraying may be done with the crudest implements. Corn- 
brooms and whitewash brushes have been used with good 
effect in some cases, but for uniformly good results we have 
seen nothing better than some of the modifications of the 
cyclone nozzle (Plate XXVII., Fig. 2). This nozzle was 
originally brought to public notice by Professor Riley, then 
chief of the United States Entomological Commission. When 
used in its original form, it throws a finer and more even 
spray than any nozzle which has come to our notice, yet it 
has faults which preclude its use except in very limited 
fields. It sprays very slowly and is frequently clogged by 
the coarser particles of the insecticide or by foreign sub- 
stances, the perforation through which the liquid passes out 
in spray being very small. It is then necessary to remove 
the cap and clear the nozzle. Therefore much time is con- 
sumed in its use. When first tried experimentally at 
Medford it was found that an hour was required to spray 



SPRAYING APPARATUS. 



151 




Fig. 10. Quadruple cyclone nozzle. 



thoroughly a large apple tree. Still the cyclone nozzle has 
been used to some advantage against the gypsy moth by 
uniting four nozzles in one (Fig. 
10) and slightly enlarging their aper- 
tures. The nozzles radiate some- 
what so that the spray from the 
four covers a much larger field than 
that from only one. The amount 
of the spray thrown in a given 
time, as well as the area of the 
foliage covered, is more than quad- 
rupled. Yet clogging occurs more 
frequently on account of the greater number of nozzles. 

The Vermorel modification of the cyclone nozzle (Plate 
XXIII. , Fig. 1) is an improvement on the original inven- 
tion. It throws more liquid than the cyclone but gives a 
fine, even spray which, because of its fineness, cannot be 
projected to a distance. This spray will drift on the wind, 
however, so that spraj'ing can be done for some distance to 
the leeward of the operator. Though this nozzle uses less 
of the spraying fluid than the Gem or Lowell nozzles, it 
uses more than the cyclone and therefore will spray more 
rapidly than the latter. It distributes the spray more finely 
and evenly than the Gem or Lowell nozzles and gives better 
satisfaction in spraying small trees or shrubbery. Experi- 
ments indicate that in the number of caterpillars killed, there 
is a slight difference in favor of the 
Vermorel nozzle over the nozzles 
previously mentioned. Spraying 
may be done more rapidly by at- 
taching two or more nozzles to the 
same hose by means of the Y coup- 
ling (Fig. 11). 

The Vermorel nozzle consists of 
a short brass tube bent at right 
aogles, having a coupling at one 
end by means of which it is at- 
tached to the hose and at the other 
end entering at right angles a small cylinder, which is divided 
by a transverse partition into two chambers. 




Fig. 11. Y nozzle. 



152 THE GYPSY MOTH. 

The stream from the hose is carried through the bent tube 
and enters at a tangent the anterior chamber of the cylinder. 
The posterior chamber serves as a packing box for a small 
brass rod which passes through the centre of the partition 
dividing the chambers, and lying in the axis of the cylinder, 
projects half its length in the rear, where it is terminated by 
a screw cap. Around the rod between this cap and the nut 
closing the packing box is a spiral spring which keeps the 
rod drawn back when not in use. The anterior part of the 
rod has a flange in front of the partition which prevents it 
from being drawn back out of the chamber and its anterior 
end has a fine needle point. The outer chamber of the noz- 
zle is closed by a screw cap, hollowed at its centre where it 
is perforated by a fine hole which serves as the exit for the 
spray. When this hole becomes clogged, it may be cleared 
by pressing on the cap or thumbpiece at the base of the rod, 
thus forcing the needle point out through the opening. 

The climax or Nixon nozzle is better adapted for spraying 
large orchard trees than the cyclone, as it throws a good 
spray to a considerable distance, but it is not adjustable like 
the Gem and Lowell nozzles. It is shown in Plate XXIV., 
Fig. 3. No. 1 shows the entire nozzle, No. 2 the nipple 
end of the same, and No. 3 the end of the nozzle, which 
screws over the nipple and is covered with a fine screen 
which breaks up the stream into spray. All these parts are 
fitted with standard pipe thread, and will fit corresponding 
sizes of gas pipe and hose coupling. They are made of 
various sizes which will produce spray from the density of 
a heavy fog to any coarseness that may be required, the 
smaller sizes giving the finest spray. 

The McGowen nozzle (Plate XXVII., Figs. 3, 4 and 5) 
has been used only experimentally in the gypsy-moth work. 
This is the only nozzle we have yet used which appears to 
give equal satisfaction in all kinds of spraying. It pos- 
sesses to some extent the qualities of all the nozzles previ- 
ously mentioned. It can be regulated at will to throw a fine 
spray, project a coarse spray to some distance, or send a 
stream to a considerable height, where it will break into 
fine drops. Its effective use, however, requires some skill 
and mechanical kuowledge on the part of the workman. 



SPRAYING APPARATUS. 153 

Fig. 3 represents a side view of the nozzle and a cross 
section of the piston about three-fourths natural size. The 
cylinder u projects at right angles from the top of the tube 
10. This cylinder is closed at the end by a bevelled block. 
The orifice v is closed by a sliding piston which is composed 
of one or two pieces. The cross section of the piston shown 
in Fig. 7 represents the form having two parts, an inner 
piston which can be screwed out, as represented by the dot- 
ted line e, and an outer part or sleeve c. By turning the 
screw s the spray can be changed instantly from a long- 
range spray suitable for orchards to a spray fine and mist- 
like. However the opening may be adjusted, it so remains, 
except when obstructions become lodged in the nozzle. The 
spring x is designed to hold the sliding valve in position 
except when obstructions are forced into the nozzle. As 
such obstructions prevent the passage of the fluid, the pres- 
sure upon the walls of the opening in the nozzle instantly 
increases. This forces the piston back from the outlet orifice 
so that the opening will admit the passage of any object not 
larger than one-fifth by three-sixteenths inch. When the 
obstruction passes out, the force of the spring sets the valve 
back into position and the nozzle works again as desired. 
The tension of the spring x can be varied by moving the ring 
z up or down. Figs. 4 and 5 represent two pistons, each 
composed of one piece. No. 4 is adapted for long-distance 
work; No. 5 is adapted for short-distance work, as it 
throws a very fine spray which cannot be forced to a dis- 
tance. These parts are made to be used where a change of 
spray is not desirable. All the pistons are interchangeable. 
Fig. 6, Plate XXVII., represents a lighter nozzle, designed 
for knapsack pumps. The spray is fan shaped. The advan- 
tages of such a nozzle are evident. When the spraying is 
done by means of a pole extension, such small particles as 
clog some other nozzles are quickly released without anv 
delay or stopping of the pump or lowering the pole to clear 
the nozzle. 

The extension nozzle consists of a metal pipe, sometimes 
inclosed in a bamboo pole. It is made to enable the opera- 
tor to raise the nozzle to a height of twelve feet or more 
from the ground, so that orchard trees may be sprayed with- 



154 THE GYPSY MOTH. 

out climbing. The extension nozzles ordinarily made, being 
but five or six feet in length, are not particularly useful for 
this purpose, but may be used to advantage when the work- 
man stands on a firm step-ladder. In the work on the gypsy 
moth a light wooden pole twelve feet in length was used 
in orchard spraying. The nozzle and hose were attached 
to this pole by means of snap hooks, or the nozzle was 
secured to the end of the pole by means of a cap provided 
for the purpose. In using this pole the workman carried 
the lower end in a socket attached to a belt around the 
waist. 

Power Spraying Machines for Orchards and Field Crops. 

Several horse-power spraying machines have been pro- 
duced with the intent of saving time, labor and money to 
the user. In using such of these machines as we have seen, 
it is necessary to keep the horse moving in order to work 
the pump by horse power, and it is difficult to get sufficient 
power without driving too fast to give time for thoroughly 
spraying the trees in passing. Therefore in spraying trees 
the pump must be operated by hand. These machines are 
valuable in spraying potatoes and other crops grown on the 
ground. 

The "giant, automatic power sprayer" (Plate XXVI., Fig. 
1) has been adopted for use in the gypsy-moth work, but as 
yet has not been thoroughly tested in the field. It consists 
of a sixty-gallon oak tank suspended between two wheels 
with wide tires. The diameter of the wheel is three and 
one-half feet. The frame is strongly made to enable the 
operator to use the machine upon rough ground. Endless 
sprocket gears attached to the wheels communicate the power 
to the handle of the pump by means of a shaft. The gear- 
ing may be thrown out of action in an instant to prevent 
waste when it is not desired to operate the sprayer. The 
pump can be disconnected from the horse-power machinery 
and operated by hand in spraying large trees. This sprayer 
in operation is shown in Plate XXVIII. Several steam 
spraying machines have been invented, but we have had 
no experience in their use. 



SPRAYING APPARATUS. 155 

The Care of Spraying Machinery, 
The operations of spraying are frequently more or less 
delayed by minor accidents or imperfect working of parts 
of the machinery. The action of the insecticide mixtures 
corrodes certain parts and the pumps require constant at- 
tention to keep them in good working order. Unless their 
construction is understood by either the workmen or the man 
in charge, considerable delay and loss of time are occasioned 
by sending the pumps away for repairs or awaiting the 
services of experts called in to remedy the difficulty. Yet 
most of the trouble may be easily and quickly remedied if 
the men using the apparatus have a sufficient knowledge of 
the different parts of the pump to take out those that work 
imperfectly, repair and replace them. Most of the delays in 
the field are caused by either a clogging of the strainer in 
the tank, some obstruction in the valves or the wearing 
of the packing of the piston in the cylinder. 

Before the spraying apparatus is sent into the field in 
the spring, it should be thoroughly overhauled and tested. 
While the spraying is in progress, each of the spraying 
gangs should be furnished with a tool box containing 
wrenches, tools, packing and other materials which are use- 
ful in taking apart the pumps and making repairs. Mr. E. 
C. Ware, who superintended the spraying teams in 1891, 
gives the following information and directions in regard to 
the care of pumps in the field : — 

If a pump fails to throw a stream, it is well to put some 
clean water in at the top, as it is quite often the case that 
the valves are made or lined with leather, which, in drying, 
has become hard or warped out of shape. If the pump is 
an old one and the valves are of leather, it may require new 
valves before it can be made to work. If the pump still 
fails to operate satisfactorily, examine the strainer to see 
whether it has become clogged, as the trouble with the pump 
can be quite often found at the bottom of the strainer. If the 
pump has not been used for a day or two, the strainer may 
have become corroded. Sediment from the material used for 
spraying will sometimes dry on the meshes of the strainer so 
as to prevent the passing of the liquid through the pump. 



156 THE GYPSY MOTH. 

When Paris green, lime, arsenate of lead or similar com- 
positions are used with glucose or other adhesive constituents, 
and the pump is not thoroughly cleaned after using, trouble 
with the valves may be expected. When the trouble cannot be 
found at the strainer, it is well to clean the valves thoroughly, 
being careful to put them back in their original positions, 
seeing that the packing is clean and in place before putting 
the screws back or screwing any nuts down. In tightening 
the nuts or screws, put them down until they come to an 
easy bearing all around ; after which go over them again and 
settle them down tightly. In case the pump should be a 
heavy one having a piston working through packing, and the 
liquid escapes around the piston, loosen the large nut and 
take out the ring which will be found pressed in by the nut. 
If the packing which will probably be found there is hard 
and dry, it will be well to replace it with some hemp packing 
such as is used by steam fitters (or if this is not at hand, 
with cotton wicking), saturating it with heavy oil or tallow 
mixed with a liberal supply of black lead (graphite). Soak 
the packing thoroughly and wind it loosely about the piston, 
pushing it in the mean time toward the pump until you have 
about as much wound on as the ring will push in without 
preventing the nut from catching. Then screw the nut up 
as far as it will go without preventing the pump from work- 
ing easily. It is not well to screw it up too tightly at first, 
but to turn it a little at a time, just enough to keep the 
pump from leaking. 

In connecting hose to pumps, it will be found necessary 
to use rubber washers at all connections to prevent leakage 
when couplings are screwed together. Wherever the cast- 
ings or other parts of the pump are broken by accident, much 
time may be saved if duplicate parts are kept ready for such 
an emergency. Before the pumps are stored at the end of 
the spraying season, they should be taken apart and care- 
fully cleaned and oiled. 

When to Spray for the Gypsy Moth. 
Spraying should be done early in the season, as soon as 
the leaves are well grown, for at that time there is least 
risk of injury to the foliage. The insecticide also will be 



WHEN TO SPRAY. 157 

more effective if applied soon after the caterpillars hatch. 
As the young gypsy-moth caterpillars hatch at intervals 
from the latter part of April until the middle of June, and 
as the leaves are constantly growing during the early part 
of the season, thereby offering daily more fresh unpoisoned 
surface upon which the caterpillars may feed, it may be neces- 
sary to spray once or twice more in May or June. Spraying 
with the best insecticides known (arsenate of lead excepted), 
if done late in the season, has little effect on the gypsy- moth 
caterpillars where they are numerous, as they will strip all 
foliage from the trees before being seriously affected by the 
poison. The uselessness of such spraying is shown by the 
illustrations in plates IX., XI. and XVI. The caterpillars 
thus destroyed the foliage in the Swampscott woods early in 
August, after the trees had been sprayed twice with Paris 
green . * 

It is well not to spray fruit trees when in blossom. If 
sprayed at all at that time, the work should be done with a 
nozzle throwing a fine, mist-like spray. A coarser spray is 
likely to injure the blossoms, as well as to wash off the 
pollen. There is danger also of poisoning bees. Prof. F. 
M. Webster, entomologist of the Ohio experiment station, 
has experimented by spraying apple trees in full bloom and 
giving bees access under natural conditions to the sprayed 
blossoms. Many of the bees which visited the trees died 
suddenly, as well as the young larvae of a brood from 
uncapped cells. Arsenic was found in the contents of the 
abdomen as well as on the external parts. The bees all gave 
evidence of having died from the effects of arsenic which 
could only have been introduced from without the hive. If 
the pollen is washed off the blossoms by the spraying and 
the bees which distribute pollen are killed by the poison, the 
spraying of fruit trees when in blossom will affect their 
fruitfulness. 

Spraying should not be done during showers or after 
showers before the leaves dry, or when a heavy dew is 
on the foliage. When spraying is done during showers, 

* Many of the failures that have been recorded in spraying for other insects may 
be traced to the fact that the work was done too late, and not until after the injury 
was so serious that the spraying could not stop it in time to save the foliage. 



158 THE GYPSY MOTH. 

much of the poison will be washed off or gather in spots. 
If the trees are sprayed in dry weather or at a time in the 
day when the leaves are dry, the poison adheres to the leaves 
as it falls and is thus most effective. 

Hoiv to Spray for the Gypsy Moth. 

In many cases spraying for insect pests is a failure. Where 
tender plants and choice fruit trees are sprayed, more harm 
than good is often done. This is not to be attributed, how- 
ever, to the method, but to either poor machinery or to 
ignorance or carelessness in the use of insecticides. When 
spraying is thoroughly and carefully done according to the 
rules given by the best authorities, it will almost always give 
good results with most leaf-eating insects. Yet, as has been 
shown, the most careful spraying with the best insecticides 
may fail to check the gypsy moth. If spraying is done 
when the caterpillars are young and feeding mostly on the 
lower surface of the leaves, it will be most effective. Use 
not less than fifteen pounds of arsenate of lead and two 
quarts of -glucose to one hundred and fifty gallons of water. 
Be sure that the acetate of lead is dissolved in water (warm 
if need be) before it enters the tank. Stir the mixture con- 
stantly and spray evenly and thoroughly with a fine spray. 
If this does not kill, double the dose. 

Spray fruit trees to as high a point as possible from 
the ground by the use of a long pole or extension with any 
nozzle which will throw a very fine spray, spraying always 
in such a way as to reach the under side of the leaves. 

On tall shade or forest trees spraying may be best accom- 
plished by the use of a ladder. A nozzle which will throw 
a coarse spray to a distance, like the Gem, Lowell, Nixon 
or McGowen, may be used. Often the lower limbs may be 
sprayed from the ground by means of a pole. The pole can- 
not be so well handled in the tree, and the workman can 
spray best by climbing up the main trunks and branches 
and spraying from below as he climbs. If the spraying is 
done later in the season, particular attention must be paid 
to the ends of the branches and to the tops of the trees, for 
many of the larger caterpillars crawl to the very tips of the 
branches and to the tops of the trees to feed. 



PLANTS INJURED. 159 

Injury to Plants caused by Spraying. 
The strong prejudice against the use of Paris green for 
spraying which was met with in Medford in 1891 was partly 
caused by the belief that both trees and garden plants would 
be injured or killed thereby. This belief was shared by many 
people and was largely based upon the results of the work 
of the first commission, as observed in 1890. Many indi- 
viduals who had experimented with London purple and Paris 
green in an attempt to protect their trees had succeeded 
only in destroying the foliage. It is true that the foliage 
of many trees was injured in 1890, and that to a less extent 
this occurred in the work of 1891. Yet much of the appar- 
ent injury was effected by other causes than spraying. In 
the investigation of complaints that the foliage of trees had 
been burned, it was found that in some cases the injured 
trees had not been sprayed. In at least one case the sup- 
posed burning was caused by the effect of a late frost. A 
blight upon fruit trees early in the season closely resembled, 
upon superficial examination, the appearance produced by 
arsenical burning. Later in the season, during the drier 
portion of the summer, many leaves on trees, which had 
not been sprayed, turned yellow and fell, presenting much 
the same appearance as was observed on foMage which had 
been burned by spraying. Many reports were received that 
trees had been killed by spraying, but in most of these cases 
it was not clearly proved that death was not due to some 
other cause. Still there is evidence that some young trees 
were either killed by spraying or were so weakened by 
burning or defoliation resulting from spraying that they 
succumbed to the heat of the summer. Such a result is un- 
usual, however. An apple tree which was sprayed in 1890 
with the contents of fifteen tanks of the Paris green mixture, 
each tank containing a pound of Paris green, was not per- 
manently injured. It is said that many young and tender 
plants in gardens were not only seriously injured but actually 
killed by spraying; yet where this happened it was prob- 
ably due to some ignorance or carelessness in the use of the 
insecticide. Some species of trees are more susceptible than 
others to the effects of the poison. The foliage of plum 



160 THE GYPSY MOTH. 

trees and especially that of peach trees is often destroyed 
by an application which will not injure the apple or many 
other species. There appears to be a difference among 
varieties of trees of the same species in their susceptibility 
to poison, and some individuals of the same variety seem 
more susceptible to injury than others. This is also true 
of shrubs and garden plants. 

Causes of the Burning Effect. 
We have already stated that the burning of foliage by 
arsenites appears to be caused by the soluble arsenic in the 
insecticide ; yet it is known that poisons like Paris green, 
which are comparatively insoluble in water, will burn the 
foliage under natural conditions if applied in great strength. 
This seems to indicate that the arsenic on the leaf is dis- 
solved more or less by dews and rains, the dehydrating 
effects of the sun's rays, a moist atmosphere or the 
exhalations from the leaf, or by all combined. We have 
noted that although experiments with arsenites performed 
in a dry atmosphere in the laboratory produced no burn- 
ing effect, the same strength of material burned badly out 
of doors. Professor Fernald's experiments in the insectary 
indicate that Paris green burns more in warm damp weather 
than in cool dry weather.* The larger the amount of 
arsenic deposited on the leaf the greater will be the amount 
eventually dissolved, and the greater the burning effect. If 
the liquid is distributed evenly in minute drops over the leaf, 
there is less danger of burning than if it is distributed in 
large drops, or if the tree is so copiously showered as to 
cause the arsenic to settle and accumulate in spots upon the 
leaf. "Wherever such accumulations occur, the burning is 
the more serious and the injury spreads from the burned 
spots. Therefore, there will be the least burning from a 
fine spray, lightly and evenly distributed. 

How to prevent Burning the Foliage. 
What should be done and what avoided to prevent or lessen 
the burning of the foliage may be summarized as follows : — 

* Bulletin No. 19, Hatch Experiment Station, page 118, May, 1892. 



PREVENTION OF BURNING. 161 

1. Avoid the use of London purple. 

2. If Paris green is used, keep the spraying liquid con- 
stantly and thoroughly agitated. 

3. Use only a very fine spray and distribute it lightly. 
This applies especially to tender plants and valuable fruit 
trees where burning may mean serious loss. 

4. Do not let the spraying liquid stand in the tank but 
use it as soon as mixed. 

5. Spray early in the season when the injury to leaves 
will be least. 

6. If Paris green does not give good results, use arsenate 
of lead, which will not burn if properly mixed and applied. 

Reports of Injury to Man and Animals by Spraying. 
The prejudice against spraying in Medford and other 
towns was intensified by the belief that there was danger of 
fatal poisoning to man and animals. When the spraying 
was in progress, sensational reports were circulated. State- 
ments were made in the daily press that a man had died 
from the effects of chewing leaves taken from trees sprayed 
in Medford, and that a child had been fatally poisoned by 
eating bread and butter on which some of the spray had 
fallen from the trees. On this at least one newspaper editor 
advised his readers to shoot at sight the workmen employed 
in spraying. It was reported that there was great danger 
from eating sprayed fruit. Several quarts of cherries which 
had been taken from sprayed trees and preserved in jars were 
analyzed, and no trace of arsenic was found. Yet even before 
they were analyzed, it was reported that they had been sent 
to Amherst and that arsenic enough had been found on them 
to kill a dozen people. A large portion of the cherries on 
these trees were stolen by boys or given away, yet no im- 
mediate mortality occurred among the juveniles of the neigh- 
borhood. It was frequently reported that people had been 
badly poisoned by having a spray thrown in their faces. It 
is possible that this statement had some slight foundation in 
fact. While in eating fruit there is little danger of the con- 
sumption of sufficient poison to have any appreciable effect 
on the system, there is a certain amount of danger from the 
absorption or inhalation of arsenic, and great care should 



162 THE GYPSY MOTH. 

be alwa3 r s exercised in its use. About ten per cent, of the 
men employed in spraying suffered more or less from arseni- 
cal poisoning. Some appeared to be much more susceptible 
to its effects than others. This subject is more fully treated 
in Appendix F, where instances of the ill effects produced by 
the careless use of arsenic are given. Numerous sensational 
tales were promulgated in regard to the effect produced on 
animals by eating grass or foliage poisoned with Paris green. 
That there is no danger of serious results to the larger 
domestic animals from ordinary spraying has been proved 
by Prof. A. J. Cook's experiments.* He fed to his horse 
and to sheep grass on which the poison had been allowed 
to drop copiously from sprayed trees. We have frequently 
fed a horse in the same way without any apparent harm to 
the animal. A Medio rd milkman was accustomed to take 
as a gift the grass which people feared to use, it having been 
cut on lawns where the trees had been sprayed. This grass 
formed the principal food of his cows during the summer and 
they showed no ill effects. At one farm in Somerville, where 
the trees were liberally sprayed, three cows suddenly died. 
A suit was threatened, but on account of lack of evidence it 
never came into court, f Several flocks of fowls were stricken 
with sudden mortality immediately after the trees which hung 
over hen yards had been sprayed. Fowls show a great sus- 
ceptibility to arsenical poisons. It is a question, however, 
whether the fowls were killed by eating poisoned caterpillars 
or grass on which the spraying liquid fell, or whether they 
did not die from some epidemic disease. The matter was 
not fully investigated, One instance was noted where a hen 
died just as the workmen walked into the yard to begin 
spraying. The owner was immediately notified so that the 
impression might be avoided that it was killed by Paris 
green. J 



* Bulletin No. 53, Agricultural College of Michigan Experiment Station, August, 
1889. 

t Cows have fed without apparent injury on grass under trees which have been 
twice sprayed with arsenate of lead at a strength of fifteen pounds to one hundred 
and fifty gallons of water. 

% If wild birds are likely to be destroyed by eating poisoned vegetation or poisoned 
insects, the benefits derived from spraying must be largely discounted, as birds are 
most useful as insect destroyers. 



CONTACT INSECTICIDES. 163 



Spraying with Contact Insecticides. 

When it was seen that spraying the foliage with Paris 
green had little effect on the larger gypsy-moth caterpillars, 
experiments were made with insecticides which were intended 
to kill by contact. This was done to find a means of dispos- 
ing of the masses of caterpillars which did not seem to be 
much affected by the use of Paris green and which clustered 
on many trees where fire could not be used. Contact in- 
secticides, when of a strength sufficient to kill the gypsy- 
moth caterpillars, are likely to cause injury when used on the 
foliage. Therefore they can only be used to advantage as a 
last resort where the caterpillars have stripped trees or 
where they are clustered in such numbers on the trunks 
as to make it less expensive to spray with an insecticide 
than to kill them by hand. 

Kerosene emulsion was first tried. A strong emulsion 
gave fairly good results but its preparation in the field was 
not economical. The only way in which it could be made to 
give satisfactory results was to mix it at a central point and 
distribute it to the different towns. When it was made in 
the field the men did not get uniform results. 

Fish oil and whale oil soap gave better satisfaction when 
used as follows : — 

Take one pound of whale oil soap and slice into thin, 
small pieces. Place the pieces of soap in a pail and add 
about a gallon of boiling or nearly boiling water ; then stir 
until the soap is dissolved ; dilute at the rate of one pound 
of soap to twenty gallons of water. This formula was pre- 
pared by Mr. E. P. Felt. 

Solutions made from soap powders also proved effective. 
The following formula was prepared by Supt. F. H. Jones : — 

Place one pound of "Gold Dust" in a pail; add one 
gallon of lukewarm (not hot) water; stir briskly until the 
powder is dissolved ; then add three gallons of cold water ; 
stir well. 

Where the larvae and pupae are clustered together on the 
trunks of trees and in stone walls or other sheltered places, 
they should.be well drenched with the solution. The hand 
tank (Fig. 1, page 120) and Gem nozzle were found useful 



164 THE GYPSY MOTH. 

in spraying with contact insecticides. A tree in Swamp- 
scott, the trunk of which was covered with caterpillars, 
was sprayed, killing nearly all at one spraying. Excellent 
results were obtained wherever the liquid was carefully 
mixed and applied. It is poor economy, however, to use 
contact insecticides except where the larvte are very numer- 
ous, for elsewhere they may be more rapidly and cheaply 
killed by hand, either by burlapping the trees or by other 
methods. 

While the use of soap powders upon the gypsy moth has 
some advantages, it is not to be recommended except in the 
most extreme cases and with the exercise of great care and 
judgment. 

Measures for Destroying all Forms of the Moth. 
The methods thus far described have each been intended 
for the destruction of a particular form of the moth. The 
methods hereinafter described are intended to facilitate or 
secure the destruction of all forms of the moth, and have 
been used with a view to preventing the creature's spread 
and securing its extermination. It has sometimes become 
necessary to destroy all vegetation in an infested spot in 
order to prevent the moth's rapid spread and wide dissemina- 
tion. For this purpose fire and the axe have been resorted to. 

Cutting and Burning. 
As an exterminative method for use in wooded tracts, the 
felling of trees and their destruction, together with that of 
all other vegetation, by means of fire has no equal in point 
of expedition and economy. This can only be done advan- 
tageously, however, on lands where the timber is of little 
value, as the damage caused and expense incurred by treating 
valuable woodland in this way would be great. This method 
is expedient only where a badly infested spot is found in 
woods not otherwise infested and where by vigorous and 
immediate exterminative methods the pest may be stamped 
out. When a colony of this kind is discovered, the trees may 
be felled to best advantage in the fall or early winter. At the 
same time the undergrowth can be cut close to the ground and 
burned together with the tree-brush, or it may be left to dry 



CUTTING AND BURNING. 165 

where it falls and burned later with the wood by means of a 
running fire. Fire will dispose of the eggs upon the trees and 
undergrowth, yet many will remain among the dried leaves 
on the ground. In order to secure the destruction of the 
caterpillars which hatch from these, the territory cleared 
should be thoroughly burned over in the spring with the 
cyclone burner. This should be done shortly after the young 
caterpillars hatch. The cutting and binning should extend 
for several hundred feet beyond the utmost confines of the 
infested spot. The immediate effect of this treatment will 
be to destroy all vegetation above ground, and as a conse- 
quence any young caterpillars not reached by the flames will 
starve. From the stumps of deciduous trees cut down, 
sprouts will in time spring up. The burning will not kill 
the roots and a new growth of trees will finally develop. 
There will be no sprouts from the older coniferous trees, 
as they do not renew their growth in this w r ay, but are 
replaced by deciduous trees. The burning is not entirely 
without beneficial effect on the land. The ashes resulting 
from the combustion of wood and dry leaves stimulate the 
growth of such roots as are buried in the ground or beneath 
the leaves and which send forth shoots under the influence 
of sun and rain. Within a few months the entire burned 
area will be covered with a growth of young plants and trees. 

A locality in Woburn where timber land is being cleared 
in this way is shown in our illustration (Plate XXIX.). 
The appearance of this woodland when attacked by the 
gypsy moth may be seen by referring to Plate XVII. The 
owner was willing that the ground should be cleared in 
order to secure relief from the pest. The trees were first 
cut down and the wood cut in eight-foot lengths and the 
brush piled and burned, leaving the land ready for the final 
burning with the cyclone burner in the spring. 

Valuable woodlands generally infested have been treated 
by clearing away the undergrowth so as to leave nothing on 
the ground for the insects to feed upon. In this work great 
care must be taken to avoid injuring the trees by making too 
hot a fire about their trunks. It is better to rake away the 
dead leaves and undergrowth from the bases of the trees and 
burn them than to risk girdling the trees by running a hot 



166 THE GYPSY MOTH. 

lire close to their trunks. They may then be banded with 
insect lime so that the caterpillars may find nothing on which 
to feed, or they may be burlapped and the caterpillars caught 
under the burlaps. This method will not injure the growing 
timber, and if a cleared grove is desired the timber may be 
thinned by cutting away the least valuable trees. This will 
render the later treatment less expensive. 

In 1891 nearly all the trees were felled on a tract of more 
than one hundred acres near Myrtle Street, Medford, where 
the moths were first introduced. (See Plate XXX.) The 
undergrowth was then burned by a running fire. The ex- 
termination of the moths at that place was not then attempted, 
but the work was done as an experiment in preventing their 
increase and spread from a badly infested locality. As such 
it was a success. A fire run through dry leaves and under- 
growth before the middle of May will destroy the greater 
portion of the young larvae if done when they are small, and 
when the dry vegetation burns with a quick heat. 

When worthless and badly infested trees are found in 
orchards or elsewhere, the most eft'ectual and economical 
method is to cut and burn them. Such trees are usually 
full of holes, cracks and cavities, and in such hiding places 
all forms of the moth are found in numbers. They can be 
immediately disposed of by burning the trees, thereby olr 
ating the necessity of further search and treatment. 

There is much waste land covered with undergrowth and 
scrubby trees in the infested region. It receives no care 
from its owners, being held, not for its productive value, but 
for speculative purposes. Fire often runs over such land, 
killing the bushes and young pines and injuring the larger 
growth so that it is comparatively worthless. Such land 
can be cut over with little or no loss to the owner ; indeed, 
clearing may often enhance its value. It is not well to cut 
the growth during the spring months, when the caterpillars 
are upon it, as they will be disturbed by such work and 
scattered in all directions. It is much better to cut over 
such land in the fall, and burn the brush as it is cut or let 
it lie on the ground until it is well dried and then run fire 
through it, destroying as many of the eggs of the gypsy 
moth as possible. Then when the larvae hatch in the spring, 



BUKLAPPING. 167 

there will be nothing for them to climb upon, and they may 
be all destroyed by burning the ground over with a cyclone 
burner. (See Plate XX.) If it is desired to prevent a new 
growth of brush, the ground should be burned over in August 
while the sap is in the plants, and again in the following 
spring. After such treatment the plants will not so readily 
sprout and a frequent repetition of the burning will result 
in killing their roots. 

Burlapping . 

Early in the summer of 1891 burlap or bagging was first 
used by the employees of the State Board of Agriculture as 
a means of assembling the gypsy-moth caterpillars so that 
they might be readily found and destroyed. It was noticed 
that before the caterpillars had attained half their growth, 
they daily left the leaves on which they had fed during the 
night and clustered in sheltered places, such as cavities in 
the trunks of trees or the under sides of branches or other 
natural objects. They began thus swarming in the second 
week in June. As they grew larger the tendency to seek 
shelter during the day became more and more noticeable. 
They often wandered in search of shelter, leaving trees 
which did not offer secure hiding-places and retiring to 
rubbish heaps, stone walls and other places of refuge to 
pass the day. It was seen that whenever old garments, 
cloth or paper were thrown in the forks or wound around 
the trunks or branches of infested trees, the shelter of such 
materials was sought by the larvas during the heat of the 
day. The bulky nests of the English sparrow also served 
them as hiding-places. 

The conclusion having been reached at this time that 
spraying with Paris green was only partially successful in 
destroying the caterpillars, other means of destruction were 
sought. Experiments were made to find an inexpensive yet 
durable shelter which would prove attractive to the cater- 
pillars, and which could be readily examined by the men, 
thus serving in a measure the purpose of a trap. A cheap 
eight-ounce burlap was found to be the best material for 
this puqiose. A large quantity of baled burlap was pur- 
chased and cut into strips about twelve inches wide. These 



168 



THE GYPSY MOTH. 



strips were made into rolls which the workmen carried sus- 
pended from the shoulder. Each man was provided with 
a sheath knife. When a tree was to be " burlapped," the 
end of a roll was passed around the trunk at a height of 
four or five" feet from the ground, and enough cut off to 
encircle the tree and lap sufficiently at the ends to allow 
for shrinkage. (See Plate XXXI.) The burlap was held 
in place by twine tied around both tree and cloth. (See 
Fig. 12, a.) The upper half of the burlap was turned down 
over the twine, so that it hung like a tablecloth suspended 
from a clothes line, and made a band of double thickness 
around the tree. (See Fig. 12, b.) Although the edges 
hung loosely, the centre was bound quite securely to the 

trunk of the tree. If the 
trunk and branches offered 
no better hiding-places to 
the caterpillars, most of those 
on a tree would crawl down, 
morning after morning, and 
seek the shelter of the bur- 
lap, remaining there during 
the greater part of the day. 
When thus assembled, they 
were killed by the employees 
of the Board, who daily went 
their rounds from tree to tree, raising each half of the bur- 
lap separately and cutting or crushing the caterpillars be- 
neath. Most of the larva? are found on the bark behind 
the burlap, but some are taken between the folds. When, 
in the search for larva 1 , the burlap is examined for the first 
time, it is left turned up against the tree. At the second 
examination it is turned down. It is turned up at the next 
visit, down at the next and so on. By following this plan 
any band that has been missed will attract attention. Ex- 
perience indicates that the number of caterpillars taken is 
not materially affected, whether the band is left up or down ; 
yet for general use it should be turned down, as it sheds rain 
better and presents a neater appearance. 

Where the caterpillars are massed, they may be quickly 
crushed by a wisp of straw or a wad of old cloth. Where 





*StfN 



Fig. 12. Manner of applying the burlap. 










PLATE XXXI. Putting on the burlap. 



BURLAPPIXG. 169 

few are found, they may be cut in two by the knife and 
brushed off the tree. Care must be taken not to crush them 
with the bare hand, as their hairs when brought forcibly in 
contact with the skin sometimes cause an irritation much 
like that produced by nettles. 

The burlap band in no way prevents the caterpillars from 
ascending or descending the tree, neither does it entrap those 
which it shelters. But it was soon seen that most of the 
caterpillars which descended the tree remained under the 
burlap during the day, and that others which were restlessly 
roaming about on the ground often ascended the tree to the 
same shelter. Still others, fully grown and ready to pupate, 
retired to the cover of the burlap to undergo their last trans- 
formations, and the female moths emerging would often 
deposit their eggs upon or beneath it. 

The larvae seek the burlap in greatest numbers during very 
hot weather, when they usually come down the trees in the 
early morning hours, go under the burlap and remain there 
during the heat of the day. The greater number keep on 
the shady side of the tree, moving with the sun so as to 
avoid its direct rays. A few leave the burlap during the day, 
but most of them remain until evening. Observations made 
on a small apple tree showed that an average of sixty-six 
per cent, of the larvae on the tree gathered daily under the 
burlap. This habit is illustrated by Plate XXXII. 

The following quotation from the notes of Mr. W. L. 
Tower, one of the inspectors engaged in the gypsy-moth 
work, indicates that the antipathy the larger larvae have for 
sunlight is not uniformly shared by the younger or smaller 
individuals : — 

The small larvae on the tree were less restless and were disposed 
to remain longer in the sun than were the older ones. Some of 
the smaller ones would remain all day in the snn on the upper side 
of a branch, and in one or two cases when placed in a shady place 
on the tree returned to their first position in the sunshine. 

The burlap band to be effective must entirely encircle 
the trunk, and its edges must hang loosely. If under the 
influence of sun and rain it shrinks too closely to the tree, 
the larvae may not be able to crawl beneath it. This may be 



170 THE GYPSY MOTH. 

obviated by cutting the burlap once or twice from its edges 
nearly to the twine on the side of the tree opposite the lapped 
ends. This will facilitate the entrance of the larva?, as they 
can easily push their way under the loose corners. If a 
large cord is used to bind the burlap to the tree, there will 
be more room left under the upper half of the burlap when 
it is turned down. When the larvae are very numerous, the 
burlap may be tacked on and pleats taken in it, to afford 
more room for the larvae to pass beneath. On large trees, 
where the trunk is of irregular conformation, tacks will 
be sometimes required to hold the burlap to the tree. 

To those familiar with the habits of the moth, other devices 
which might serve a similar purpose will occur. Old tin 
cans or wisps of hay or straw may be placed in the forks of 
branches or near the roots of trees or beneath hedges to 
attract the caterpillars, which may be then disposed of by 
fire. Old blankets hung on fences or walls near infested 
trees will collect great numbers of caterpillars. 

When caterpillars were found to be plentiful in shrub- 
bery, stakes with pieces of burlap attached were frequently 
driven into the ground in the midst of the bushes. This 
made an attractive shelter for the caterpillars, and many were 
assembled and destroyed. Burlap was often left in the forks 
of branches or thrown over rubbish or stone heaps in badly 
infested localities. If it was repeatedly examined, many 
caterpillars were found and destroyed. It was early noted 
that not all the caterpillars would come down from the larger 
trees, such as street elms, but that some of them would 
remain in the upper part of the tree. In such cases bur- 
laps were banded about the trunk or branches at a height of 
twenty or twenty-five feet from the ground. An examina- 
tion of these burlaps necessitated the use of a ladder, but 
the results often justified the time and labor expended. 

The only considerable expense required by the burlapping 
method is that of labor. To secure the best results the 
bands must be examined each day so long as any form of the 
moth can be found beneath them. Old cloth will answer 
the purpose equally as Avell as burlap. 

There are no valid objections which can be urged to the 
use of burlap. There seems to be no injury to the tree 



■ 













PLATE XXXII. Section of burlap band raised, showing gypsy moth. 

caterpillars that had gathered beneath it on the 

trunk of an eim tree. 



BURLAPPING. 171 

from its use, although if it is not visited often and watched 
carefully, other insects injurious to trees will use it as a 
hiding-place. In the fall the larvae of the codling moth 
(Carpocapsa pomonella, Linn.) will crawl under the burlap 
and gnaw away the bark while preparing a place to pupate ; 
but if the burlap is watched and all injurious insects found 
beneath it destroyed, its use will prove of great benefit to 
the tree. Should it be applied to very young fruit trees 
(which is seldom necessary, as a cloth thrown in a fork 
of the tree may be used in such cases), there may be some 
little danger that the cord, if large, will shrink too tightly 
and crease the bark of the growing tree. 

Though the use of the burlap for the destruction of the 
gypsy moth grew out of observation and experiment by the 
employees of the State Board of Agriculture, later research 
in the literature of economic entomology showed that similar 
devices had been used in the past for other insects. 

Dr. Harris, in his report on the injurious insects of Massa- 
chusetts (first published in 1841), writes as follows of the 
use of bands for attracting the larvae of the codling moth : — 

Mr. Burrelle says that if any old cloth is wound around or hung 
in the crotches of the trees the apple worms will conceal themselves 
therein ; and by these means thousands of them may be obtained 
and destroyed.* 

Kollar wrote of the use of the same method in Europe : — 

The following mode of destroying the insects injurious to fruit 
trees, communicated to me by M. Scheffer of Modling, is so simple 
and yet so efficacious that I cannot do better than to lay it before 
my readers. M. Scheffer lays loosely rolled-up pieces of old cloth 
or blotting-paper in the forks of his trees. The caterpillars eat 
during the night and while the dew is on the leaves in the morn- 
ing ; but they seek protection from the heat of the day, and creep 
into these rolls for that purpose. Thus it is only in the middle of 
the day that these rolls should be examined, and the caterpillars 
concealed in them destroyed. f 



* "A treatise on some of the insects injurious to vegetation," by T. W. Harris, 
M.D., page 487. See also " New England Farmer," first series, Vol. 18, page 398. 
t " Practical Entomologist," Vol. 1, page 83. 



172 THE GYPSY MOTH. 

As Kollar resided in Austria, where the gypsy moth was 
sometimes injuriously abundant, it is probable that this crude 
means of assembling the caterpillars was used in destroying 
this species with others. 

A few people in Medford who had observed the habits of 
the gypsy moth had also used similar bandages with good 
effect prior to 1891. (See statements of James Bean, page 
29, and S. F. Weston, page 30, of this report.) 

The burlap bands are used most successfully on trees that 
are well kept and in good condition, with sound and smooth 
trunks and branches. If the trees were originally in such 
condition or were first properly prepared for the work, the 
moths were eradicated from many localities by the burlap- 
ping method alone. When trees with decaying branches, 
hollow trunks and rough or loose bark became infested, the 
caterpillars often preferred the shelter offered by such cavities 
and inequalities to that provided by the burlap. Many of 
them would not come dow r n the tree to the burlap until the 
cavities were filled or covered, the dead branches cut away 
and the loose outer bark removed by scraping. It was 
necessary also to remove rubbish, weeds and brush from the 
ground about the trees. 

There are, therefore, four auxiliary processes (all beneficial 
to trees or grounds) which must be resorted to to ensure 
the greatest measure of success in the use of burlap. They 
are : judicious pruning or trimming of trees ; treating and 
filling cavities ; removing loose bark ; removing and de- 
stroying rubbish, undergrowth and weeds. 

Pruning Infested Trees. 
To any one who has critically examined any considerable 
number of orchard or w r ayside trees in this Commonwealth, 
the insertion here of an exhaustive treatise on the pruning 
and care of trees would seem of great utility. This, how- 
ever, is not the function of this volume. It is our purpose 
to consider here only : (1) the proper removal of dead, de- 
caying or broken branches, which, if allowed to remain, offer 
hiding-places for the gypsy moth and other injurious insects ; 
(2) the removal of clusters of small shoots or suckers, which, 
growing thickly on the trunks or larger branches, offer shel- 



PRUNING INFESTED TREES. 173 

ter to the gypsy-moth caterpillars, which, by remaining in 
such hiding-places instead of going to the burlap, may escape 
destruction. At least seventy-five per cent, of the older 
orchards in the region infested by the gypsy moth have been 
either ruined or greatly injured by their owners' neglect or 
improper pruning or by both. Thousands of trees have been 
killed by having large limbs chopped or sawn oil' or other- 
wise mutilated in such a manner that the exposed and unpro- 
tected stubs have died and communicated decay to the hearts 
of the trees. This condition of so many trees, by furnishing 
numberless places of shelter for the moth, adds greatly to 
the labor of extermination. 

Dangers of Bad Pruning. — One of the most fruitful 
causes of hollows in trees in which the caterpillars may hide 
is the neglect of the simplest precautions in the amputation 
of large limbs. Wherever we go in the country, orchard 
trees may be seen with trunks disfigured by unsightly protu- 
berances and yawning cavities. Yet projecting dead stumps 
such as have assisted in bringing the trees to this condition 
are periodically left by the hand of the bungling pruner, who 
will continue in this course until he has completed the ruin 
already begun. Such trees are monuments to the ignorance or 
negligence of those who have had them in charge. Intelligent, 
capable men, careful of their other material interests, continue 
year after year to " butcher" their trees in this outrageous 
manner, as their fathers did before them, even though the 
results of such work are constantly before their eyes. 

The growth of many orchard trees has been badly directed. 
They have been pruned "up into the air," so that their long, 
tall, slender limbs have been unable to withstand the fury 
of the gale or support the loads of ice which form on them 
during winter storms. Weakened as such trees are by decay, 
the action of the wind has sent their greatest branches crash- 
ing down in ruin. The ice storm of Nov. 5, 1894, which 
visited the eastern part of this Commonwealth, destroyed 
hundreds of apple trees by breaking down most of their 
large branches ; yet we have not seen a sound, vigorous, 
well-nourished and properly pruned tree that was materially 
injured by that storm. Neither was it always the older trees 
which succumbed, for some of the oldest, having had good 



174 THE GYPSY MOTH. 

care and therefore not being weakened by the almost univer- 
sal decay, upheld their loads, survived the storm's fury and 
were not seriously injured. 

It is far better never to prune at all than to prune in an 
unscientific manner. Native forest and fruit trees never 
pruned by the hand of man grow to maturity in better con- 
dition than those in many orchards. In the forest, trees 
are pruned by nature. As they grow upward, the dense 
shade formed by their tops kills the lower branches by de- 
priving them of the sunlight. These branches decaying drop 
off or are torn away by the wind. Little or no damage to 
the resinous coniferous trees results from this process. As 
the branches usually break off close to the trunk, and the 
wood is so filled with resin as to exclude water and parasitic 
fungi, the wounds heal readily and the trunk remains per- 
fect. More injury is likely to follow to deciduous trees 
from this operation, especially when the branches are large, 
yet wounds caused by broken branches are often healed. 
The breaking is most likely to take place during the winter 
storms, when there is less danger of injury to the trunk and 
bark. Yet serious injury is often done and the weaker trees 
are frequently killed or their shape is ruined by this process 
of natural pruning. Such pruning as is required for the pur- 
poses of the gypsy-moth work will assist in forming healthy 
growth rather than retard it. 

That many apple trees are in ruins before they are fifty 
years old is almost entirely due to neglect or the ruinous 
policy pursued in their handling. Such trees well cared 
for might continue to bear fruitfully for a century.* A 
knowledge of vegetable physiology and the practical applica- 
tion to tree culture of its laws is greatly needed by those 
who have the care of trees. A knowledge of the causes of 
diseases of trees and the means of their prevention is also 
essential to the farmer, orchardist and forester. 

It is the function of roots to fix the plant in the soil and to 
absorb from it water and the soluble organic and inorganic 
crude material which is needed for growth and development. 
It is now believed by botanists that this fluid, which we will 

* Apple trees in an orchard planted in Medford by Gov. John Brooks soon after 
the Revolutionary War have borne fruit within a few years. 



BAD PRUNING. 175 

call crude sap, charged with material for the upbuilding of 
the tree, is absorbed from the soil by the roots and is forced 
upward, flowing through the trunk and branches to the 
leaves, where it is elaborated by the evaporation of water 
and the absorption of carbonic acid gas from the air. It 
then finds its way throughout the whole tree, even to the 
roots, passing through the soft bast cells of the inner bark 
just outside the cambium layer, forming, as it goes, the new 
wood and bark. 

It may be stated as a general rule that there can be no 
perfect circulation of the sap and no long-continued growth 
of new wood or bark on any branch or stump which supports 
no leaves. It would appear, then, that roots, trunk and 
branches have no inherent power of themselves to continue 
growth and extension, but must depend upon the action 
of the leaves to furnish that elaborated nutriment without 
which their continued growth and development is impossible.* 
If the new wood is formed by the sap in its descent from the 
leaves, it evidently follows that if the projecting stump of 
an amputated branch is left without leaves so 
placed as to draw the sap to its farthest ex- 
tremity, there to be elaborated and returned, 
it must die.f 

Effect of Bad Pruning. — The cut, Fig. 
13, represents a stump left on a street tree 
by the workmen employed in pruning trees 
under the direction of the city forester of 
one of our Massachusetts cities. Around 

h, , i . , . -, Fig. 1.3. Stump of a 

an unprotected stump the rain and branch left by bad 

other atmospheric influences soon begin the p iudid s- 
work of decay between the bark and the wood. The cam- 
bium layer, lacking circulation, dries up; insects enter; 

* It is well known that the roots will for a time perform their functions without 
the assistance of the leaves, and that growth of different parts of the tree occurs at a 
time when there are no leaves upon it. But this growth is made by the absorption 
of water by the roots and by the use of reserve material. If a tree is continually 
deprived of its leaves until its reserve material is exhausted, it will die. 

t It is well known that there are some exceptions to this rule. Certain vigorous 
trees will push out shoots from latent buds near the end of the amputated branch, 
and leaves are formed, which by their functions enable the tree to cover the wound. 
Willow trunks and branches deprived of their leaves and left upon the ground have 
thrown out foliage and roots and grown into vigorous trees. 




176 



THE GYPSY MOTH. 




the bark becomes loosened, warping away from the wood 
and finally falling oft*. This condition, so familiar to ob- 
serving people, may be seen by reference to Fig. 14, which 
represents an extreme case. Nevertheless, in pruning, 
such stumps are commonly (we might say usually) left, 
not only by farmers and orchardists, but also by the em- 
ployees of city street departments and park commissions 
and even by the workmen employed in 
public forest reservations. The stump 
left exposed to sun, rain and the action 
of the frost cracks. Water enters and 
deca}^ sets in which gradually extends 
through the wood cells down into the 
trunk. Therefore each stump left pro- 
jecting eventually produces decay in that 
part of the tree with which it connects. 
fig. 14. The stump dies Fig. 15 shows a short section of the trunk 

back, injuring the trunk. „ -. . , . < , 

ot a tree on which such a stump has been 
left. The stump shown at the right indicates the remark- 
able effort made on the part of the tree to cover the wound ; 
yet in the course of years the wood has 
been eaten away by rot and the wound 
has never healed. Decay has entered 
the heart of the tree and is fast de- 
stroying it. Had the branch been cut 
even with the surface of the trunk and 
the wound properly treated, it might 
have been covered with new growth of 
wood, and decay might have been pre- 
vented. 

Wounds on vigorous trees caused by 
ainedbythe removal of small branches in this 
bad pruning. manner sometimes heal over because of 

the small size of the branches and the comparative short- 
ness of the stumps. But as the stump often decays be- 
fore the wound heals, injury to the tree results, and in 
any case an awkward protuberance is formed on the 
trunk. From such misshapen parts shoots or suckers usu- 
ally spring. Another section of a trunk is here shown. 




METHOD OF PRUNING. 



177 




Fig. 16. Excrescence 
caused by bad pruning. 



(Fig. 16.) The wound has nearly healed, yet decay has set 

in and an unsightly excrescence has been formed on the 

trunk of the tree in the effort of healing. If the wound is 

well covered by the new growth of wood 

before injury has been done by the rot, 

the progress of decay is stopped. In 

order to heal readily, a wound caused 

by the removal of a branch should be so 

made that the sap on its way to the roots 

may come in contact with the entire edge 

of the wound without deviating from a 

direct course. 

The Procter Method. — Evidently, then, 
no portion of the amputated branch should 
be left, but the cut should be made close to 
and perfectly even with the outline of the 
trunk or limb from which the branch is removed, without regard 
to the size of the wound thus made. When this is done, 
the elaborated sap flows over the wound from the edoes, 
forming callus first at the top and sides, and gradually 
covers it with healthy, straight-grained wood. The wound 
is thus healed over and the decay of the trunk is pre- 
vented. This healing is gradual and may require years 
for accomplishment, especially if the limb removed is large 
and the tree old and not vigorous. The annual wood-rinjj: 
being thickest on a young tree, wounds made on such a tree 
will heal more quickly than on an old tree. Wounds made 
near the top of a growing tree heal more readily than those 
near the base, for the reason that the annual wood-ring is 
thickest at the top. If the wound is left exposed to the sun 
and wind during the time required for healing, its surface 
invites decay. To prevent this we must protect the wound 
at once by applying shellac or coal tar to its entire surface. 
The use of grafting wax or other thick coatings for such a 
purpose is not recommended, as they are likely to be cracked 
or pushed off" by the growth of the new bark and thus leave 
the wood comparatively unprotected. A solution of shellac 
and alcohol, such as is commonly used by painters, is an ex- 
cellent wood preservative, as it closes the wound, prevents 



178 THE GYPSY MOTH. 

the exudation of crude sap, commonly called "bleeding," and 
is not open to the objection which applies to grafting wax. 
Paint is often used. Thick mineral paint mixed with linseed 
oil has given satisfactory results at the Massachusetts Agri- 
cultural College at Amherst, and is recommended by Prof. 
S. T. Maynard. Coal tar has been long used in Europe 
as the best substance known for this purpose. It needs 
no preparation aside from an occasional warming in cold 
weather, and may be readily applied with a painter's brush. 
This substance will not injure the wood, but, on the con- 
trary, is one of the most perfect wood preservatives known. 
If pruning is done with discretion at the right season, 
the trunk being not already decayed, and if the tar is 
applied at once on the removal of the branch, the wood 
will remain sound, and, except in the case of very old 
and feeble trees, the new growth will in time cover the 
wound. Decay may be prevented or delayed even in old 
trees by such treatment. Coal tar should be used with some 
caution on cherry and plum trees, as it may injure the tree 
if applied to the bark. Wounds on the maple and elm, 
which often "bleed," may need more than one application 
of coal tar to stop the "bleeding." In such cases the first 
coat of tar should be well rubbed off before the second 
application. 

The two most essential rules in regard to removing limbs 
are followed in the pruning done in the gypsy-moth work. 
Although known and practised in this country at the begin- 
ning of the present century, they have been ignored by most 
American writers on tree pruning. Yet Wm. Coxe of 
Burlington, N. J., wrote in 1817 : — 

In cutting off a branch, it should be done as close as possible, 
never leaving a stump, for the bark cannot grow over it, and 
disease in the wood will inevitably follow. If the wound produced 
by the separation be very large, cover it with tar or thick paint.* 

The principles of pruning were ably set forth in 1861 by 
De Courval, as practised with perfect success for more than 
forty years in the forest of his vast estate of Pinon (Aisne), 

* Coxe on " Fruit Trees," 1817, page 41. 






RULES FOR PRUNING. 179 

France. Later in 18fi4 the Baron Des Cars published an 
able treatise, describing a thorough, practical system of 
forest-tree pruning, based on the principles laid down by 
De Courval. The American edition of this work (trans- 
lated from the seventh French edition) with an introduc- 
tion by Dr. Chas. S. Sargent, professor of arboriculture in 
Harvard University, is the most comprehensive work on this 
subject that has ever appeared in the English language.* 
The publication of the American edition of this work was 
made possible by the trustees of the Massachusetts Society 
for the Promotion of Agriculture, an old and honored asso- 
ciation, which has done much for the improvement of agri- 
culture in this Commonwealth. The book should be in the 
hands of every person who has the care of trees. 

Season for Pruning. — Writers on horticulture differ as 
to the best season for pruning. Each urges the advantages 
of pruning at certain seasons to increase wood growth or 
the development of fruit. Objections are frequently made 
to pruning in the winter, on account of real or supposed 
danger to the tree from exposing large wounds to the extreme 
cold. Similar objections are sometimes urged to pruning in 
the early spring and late fall, when the newly cut surfaces 
are exposed to the influence of sudden and severe frosts. 
It is frequently said by orchardists that if a tree is pruned 
in the spring, when the sap is flowing copiously, and the 
crude sap is allowed to flow down from the wound, it will 
poison the bark below and produce decay of the trunk of 
the tree. 

Such examinations as we have been able to make of the 
results of spring pruning indicate that the injury is due to 
entirely different causes, viz., the crushing of the bark and 
consequent killing of the cambium layer at the base of the 
wound or the separation of the bark from the trunk. Such 
injuries are likely to occur unless great care is used in prun- 
ing. The danger of a separation of the bark from the trunk 
below the wound and the consequent running of the crude 
sap into the cavity thus formed is always greatest during the 

* " A treatise on pruning forest and ornamental trees," by A. Des Cars, translated 
from the seventh French edition, with an introduction by Dr. Chas. S. Sargent. 
Boston, 1884. 



180 THE GYPSY MOTH. 

time of the year when the bark peels most readily. In ex- 
planation of this, we cannot do better than to quote Prof. R. 
Hartig of the University of Munich, whose pathological work 
is a model of thoroughness and scientific accuracy : — 

At the time when the cambium is active, it is quite impossible 
to prevent the cortex being loosened, the friction of the saw being 
sufficient to account for it. Bnt the main cause is to be traced to 
the fact that, in order to prevent the cortex being torn off, a cut is 
first of all made underneath, and during the sinking of the branch 
the lower edge of the wound is subjected to severe pressure. The 
cortex of the lower edge of the wound forms a pivot round which 
the sinking branch turns, and, although the effects may not be 
immediately visible, still, the crushing and tearing at that point 
kills the cambium for an inch or two from the edge of the wound. 
Of course in such a case the new growth — namely, the callus — is 
not formed at the edge of the wound, but at a considerable dis- 
tance from it, where it is covered by the cortex. The result is 
that the cortex, which was originally in intimate contact with the 
wood, becomes detached, so that a cavity is formed beneath the 
wound between the wood and the dead tissues. This cavity acts 
like a gutter to catch the rain-water that flows over the surface of 
the wound, as well as all the organisms that it may contain. This 
forms a specially suitable place for the germination of the spores 
or parasitic fungi, and it is from here that water containing the 
soluble products of decomposition finds its way by means of the 
medullary rays into the interior of the wood. This cavity is a 
gutter in every sense of the term, and at the same time the point 
of attack for fungi. Even although the surface of the wound may 
have been coated with tar immediately after pruning, this spot 
remains unprotected, and indeed it is only formed after the cortex 
has been separated from the Avood by the advancing callus. It is 
in fact the Achilles' heel of the branch wound. In pruning, the 
main object must be to prevent its formation ; but this is possible 
only if pruning be confined to autumn and winter, when growth 
is at a stand-still, and' when the cortex is less liable to be detached 
from the wood. If one also takes the precaution to support the 
branch during sawing, and at the moment of separation to push it 
clear of the wound, danger is reduced to the minimum.* 



* " The Diseases of Trees," by Trof. R. Hartig, pages 255-257. English edition by 
Dr. H. Marshall Ward, London, 1894. 



SEASON FOR PRUNING. 181 

An examination of injurious results of spring and summer 
pruning indicates that the injury sometimes extends down- 
ward and serious harm is done. 

There is a danger from the running of sap which occurs 
when pruning is done in spring or summer, aside from any 
possible harm resulting from the drain on the vitality of the 
tree. Warmth and dampness are particularly favorable for 
the germination of parasitic fungi and the progress of decay. 
Though decay may occur without the presence of these 
organisms, its progress is more rapid when they are pres- 
ent. Therefore, wounds which are constantly kept wet in 
warm weather by the flow of crude sap are most likely to 
decay. 

There are reasons also why pruning in summer is likely 
to be weakening to the tree : — 

If the term, winter pruning, is given to any removal of shoots 
during the resting period of a woody plant, we may say generally 
that winter pruning is strengthening, while summer pruning is- 
weakening. ' 

If any portion of the shoot system is taken away after it has 
passed through one summer, the structure and activity of the 
root system — that is, its power of absorption and of forcing up 
water — is such that it can nourish all the branches. At the 
beginning of the next period of activity, by cutting away some 
branches the water-consuming area is diminished. The same 
amount of pressure has therefore a reduced field of action, 
and consequently the effect on the remaining branches must be 
increased. 

By pruning in the summer we remove soft shoots with only 
recently developed leaves. The latter have yet their chief work 
to perform ; for at the commencement they are developed at the 
cost of the reserve material which is stored up in the branch, then 
comes a period at which the young leaf requires all the substance 
it assimilates from without for its own growth, and only after 
its full development does it begin to work for the benefit of 
the branch. If, therefore, a soft shoot is taken away, the older 
portions of the branch are robbed of the materials which were 
used in the unfolding of the leaves, without receiving anything in 
return from the leaves they have developed. This causes, there- 
fore, a loss to the general economy of the plant ; but, with the 



182 THE GYPSY MOTH. 

increased productiveness of our cultivated plants, such a slight 
weakening may be overlooked, if any other special advantage is 
gained.* 

Tarring the wounds gives the most satisfactory result when 
pruning is done late in the autumn or in winter, for it is 
then that the tar is best absorbed by the surface of the 
wound. When branches are cut off in spring or summer, 
the tar fails to penetrate the surface of the wound because 
of the flowing sap, and its thin superficial layer does not 
prevent the cut from drying later. In drying, cracks are 
formed, into which water and the spores of fungi may gain 
entrance. For this reason it is often necessary to apply two 
or more coats of tar to the wound. 

Having considered some of the objections to removing 
limbs in summer, it is plain that the late winter is the most 
favorable time for such pruning as is here advocated. There 
is then less exposure to extreme cold to be considered. It 
is known that certain trees have a considerable flow of sap 
in winter. It is said that the Indians were accustomed to 
draw the sap from the sugar maples in November, when 
good sap days frequently occur, f It may be better to prune 
such trees in the spring or summer. The results of pruning 
native deciduous and coniferous trees at different seasons 
of the year have never been fully observed with scientific 
accuracy, and there is much to be learned. 

Removal of Dead or Broken Branches. — Dead branches 
may be removed at any time of the year, if proper precau- 
tions are taken to avoid injuring the bark or trunk of the 
tree in the operation. If these branches are left upon the 
tree until they decay and drop off or are torn away by 
the winds, the bark loosens and forms a harboring place for 
the gypsy moth and certain other insects, which hide beneath 
it and oviposit there. Their eggs being out of sight, they 
hibernate in comparative safety until the following spring, 
when the larvre hatch and attack the foliage, thus weakening 
the tree. If dead branches are not removed, they are some- 



* "A popular treatise on the physiology of plants," by Dr. Paul Sorauer. English 
edition by Prof. F. E. Weiss, pages 137, 138. 

t "The Circulation of Sap in Plants," by W. S. Clark. Annual Report of the 
Massachusetts State Board of Agriculture, 1873-74, page 162. 



REMOVING DEAD BRANCHES. 



183 




Fig. 17. Decaying branch left on 
the trunk of tree. 



times broken off by the wind, leaving a long stump project- 
in g from the tree. The ragged surface of the break oilers 
perfect conditions for the beginning of decay, and the seams 
of the stump communicate it rapidly 
to the trunk. Fig. 17 shows a section 
of a tree trunk bearing the broken 
stump of a dead branch. The tree, 
being vigorous, has pushed forward 
callus on the branch and partially 
covered it with new wood and bark. 
This attempt at healing might have 
been successful had the branch been 
broken close to the tree ; but in this 
case the effort of the tree to heal the 
wound was of no avail. The neglect 
to remove these dead branches is often indirectly the cause 
of cavities in tree trunks. When living branches are broken 
by the wind, heavy loads of fruit or other causes, the stumps 
should be removed. Such ragged and broken snags offer 
points of attachment for parasitic fungi ; and if the break 
occurs in summer, when the sap is flowing, the conditions 
are particularly favorable for the propagation of these fungi, 
and the extension of wound rot. 

The decay of a tree trunk resulting from improper pruning 
and the neglect to remove broken branches is shown in Fig. 
18. Such rotting away of the wood of the tree as is shown 
here will not occur immediately, but is 
the result which will inevitably, in the 
course of years, follow such a policy. If 
pruning is begun on the young fruit tree 
by nipping off buds and directing shoots 
so as to form a symmetrical head, and is 
carried on with good judgment as the tree 
grows, there will be no need of the ampu- 
tation of large limbs, except such as are 
broken by accident or die from other causes. 

Amputations of the large lower branches 
of shade trees are often necessary in pruning 
for beauty and utility. In orchards bad pruning often neces- 
sitates later the removal of large, decaying hollow limbs, lest 




Fig. 18. Sectional view 
of a trunk, showing the 
result of neglect and 
had pruning. 



184 THE GYPSY MOTH. 

they break down and split off a portion of the trunk, which 
in such case is frequently hollow. The removal of such 
limbs in time may prevent injury to the trunk. These am- 
putations when necessary are merely a question of surgery ; 
and if they are performed at the right season and in the 
proper manner, and the wound is properly treated, there is 
little danger of injury to an otherwise sound tree. Where 
injury to such a tree results from the process, it is usually 
from ignorance of correct methods or carelessness in their 
use. Still, it is well to bear in mind that when a surgical 
operation is to be performed, the result depends not only on 
the skill of the operator but also on the age and vigor of the 
subject. 

The death of old decaying trees is sometimes hastened by 
the amputation of large and hollow branches. The shock 
caused by the removal of several large branches, together 
with the reduction of leaf surface, which makes it difficult 
for the tree to heal the wounds, will often kill such trees.* 
The proper method for treating the cavities of such trees will 
be spoken of later. 

Removing Large Limbs. — In this process great caution 
must be exercised : (1) not to injure the tree by the unneces- 
sary removal of too many large branches in one season ; (2) 
to avoid injury of the tree by the breaking down or falling 
of the branch; (3) to guard against accidents to work- 
men. The old rule for removing large branches was to 
cut the stump across its diameter near its base, never mak- 
ino- a cut larger than the diameter of the branch. This 
practice has already been shown to be pernicious, as the 
tree has great difficulty in covering the lower part of the 
wound with a new growth of bark. Where a large limb 
is removed in this manner, the lower part of the stump 
never becomes entirely covered, and finally decays. In saw- 
ing off a branch the first cut should never be made from 
above, as the limb is likely to split and tear away from 
the trunk. The result of such an accident as is shown in 



* If an old tree with sound trunk whose branches appear to be dying is "headed 
down " by the removal of most or all of its large branches, it may revive, throw out 
shoots and form a smaller and more vigorous head. 



REMOVING LARGE LIMBS. 



185 




;. 19. Limb breaking down 
from cut wrongly made. 



Fig. 19 may prove very serious to a tree. "Whenever it is 
necessary to amputate a large or long branch, a cut should 
he made from the under side of the 
branch, at a distance of two or three feet 
from the trunk, and should extend half 
way through its diameter, as in Fig. 20, 
line A ; another cut, B, should then be 
made farther out, extending down into 
the branch until it falls. The first cut 
will prevent the limb from breaking fi 
and splitting oil* and the bark from tear 
ing down on the tree. The stump may then be removed 
close to the trunk on the line C, cutting first from below, 
and supporting the stump so that crushing or tearing of 
the bark may again be avoided. This 
method will prevent injury to the tree 
and guard against serious accidents which 
sometimes occur when the limb is first 
cut too close to the tree. In such cases 
the outer end of the branch striking the 
ground has sometimes caused the inner 
The proper method end to rebound and strike or throw down 
the workman. Whatever method is em- 
ployed, the wound should be made perfectly smooth and even 
with the outline of the trunk by cutting or planing its sur- 
face, which should then be immediately 
covered with coal tar.* On fruit trees, 
however, it is well never to remove a 
large excrescence or shoulder (such as is 
sometimes formed at the base of a limb) 
if the wood is sound, but to cut the 
limb at its junction with the shoulder. 
Large wounds are often made in the 
tree trunk by the teeth of horses, the 
breaking down of large limbs or in other 
accidental ways. When such an acci- 
dent occurs as is shown in Fig. 21, it should receive imme- 




Fig. 20 
of removing a large limb 




Fig. 21. A trunk injured by 
the breaking of a large limb. 



* If the roughened surface left by a saw-cut is smoothed, it lessens the danger 
of decay ; and if the edges of the wound are trimmed down to the outline of the 
tree, the wound is more readily covered by the occluding callus. 



186 



THE GYPSY MOTH. 



diate attention. It is necessary to cut away the stump 
which is left and to remove as much of the wood as will be 
required to make an even surface ; also to cut away all the 
bark which has been loosened below the wound. Otherwise 
such a wound will in time present an appearance similar 
to that shown in Fig. 22, and the injury may continue to 
extend. If such wounds are not immediately treated and 
covered with coal tar, their inner surface often 
becomes decayed, threatening the life of the 
tree. If the decayed wood is carefully cut 
away and the exposed surface thoroughly 
covered with coal tar, the tree will remain 
healthy. Though the new wood and bark 
may never entirely cover the wound, there 
will be no further decay. 

A cavity treated in the manner above de- 
23. Decay has been 
stopped, and the new bark and wood have entirely covered 
the edo-es of the wound, leaving the tree in a healthy condi- 
tion. The directions given by Des Cars 
for the use of coal tar on trees are so ad- 
mirably stated that we give an extract 
from them : — 




Fig. 22. A cavity 
caused by the tearing 
away of a large limb, scribed IS SllOWn in _b lg 




Fig. 23. A cavity properly 



Coal tar has remarkable preservative prop- 
erties, and may be used with equal advantage 
ou living and dead wood. A single application 
without penetrating deeper than oi'diuary paint 
treated; decay arrested forms an impervious eoating to the wood cells, 
which would without such covering, under ex- 
ternal influences, soon become channels of decay. This simple 
application, then, produces a sort of instantaneous cauterization, 
and preserves from decay wounds caused either in pruning or by 
accident. The odor of coal tar drives away insects, or prevents 
them, by complete adherence to the wood, from injuring it. After 
long and expensive experiments the director of the parks of the 
city of Paris finally, in 1863, adopted coal tar in preference to 
other preparations used for covering tree wounds, as may be seen 
in all the principal streets of the capital. . . . 

One coat of coal tar is sufficient for wounds of ordinary size ; 
but when they are exceptionally large, a second coat may after 
a few years be well applied. In warm countries, like the south 



TREATING HOLLOW TREES. 187 

of France, the great heat of summer renders coal tar so liquid that 
it is impossible to properly treat wounds made at that season. 
In such cases another coat should be applied during the following 
winter.* 

Removing Shoots and Suckers. — Many street trees, espe- 
cially elms, which have suffered from the effects of bad 
pruning, send forth shoots or suckers from many points of 
the trunk. These shoots are believed to be detrimental 
rather than beneficial to the tree, impairing the development 
of its top and larger branches. So long as suckers are 
allowed to remain, many of the gypsy-moth caterpillars 
will seek shelter among them during the day in preference 
to going to the burlap. If suckers are carefully removed, 
no injury to the tree will result. 

Treating Hollow Trees. — When the trunks and larger limbs 
of trees are riddled with holes caused by neglect or bad 
pruning, another mode of treatment becomes necessary. 
Thousands of gypsy caterpillars which feed upon the foliage 
at night will retire through the holes to the interior of 
the hollow trunks and branches, where they secrete them- 
selves during the day, emerging at night to continue their 
destructive work under cover of the darkness. The clos- 
ing of such cavities by filling, covering or sealing them is 
an important auxiliary to the other means of extermination. 
It prevents the caterpillars from hiding and the moths 
from ovipositing within the hollow trunks and branches, 
and drives them to the burlap for shelter. If the holes 
are carefully covered in the winter, many eggs are en- 
closed within. "When they hatch in the spring, the young 
caterpillars are prevented from leaving their hiding-places 
and are thus buried alive, as it were, in the tree trunks. This 
work must be very thoroughly done to prevent the escape 
of the minute, newly hatched caterpillars. 

During the work of the first gypsy moth commission 
many holes were filled with hydraulic cement. If the hole 
was large, it was packed with stones and a coating of cement 
put on the face of this filling at the mouth of the hole. If 
the hole treated was in a large and otherwise sound trunk, 

* " Tree Pruning," by A. Des Cars, pages 58 and 59. 



188 



THE GYPSY MOTH. 




Fig. 24. • Cenieuied cavity. 



the cement, provided it was properly mixed and applied, 
remained intact for years. Small holes surrounded by sound 
wood were also tilled to advantage in this manner. The 
cement may be held effectively if laid on a strong iron wire 
netting nailed across and just within the mouth of the hole. 
Whenever cement is used on growing trees, it should be 
faced up within the growth of new bark and 
wood, so that the latter may grow over and 
hold it tightly. (See Fig. 24.) When the 
callus has already formed on the edge of 
the cavity, it should be cut away. This 
cutting w T ill stimulate new growth, and if 
the cement is properly faced up within 
the mouth of the cavity, the callus will 
eventually cover it. If the hole is so filled 
that the cement laps over the edge upon 
the bark, it is likely to prove worse than 
useless, as the growing bark beneath the cement will throw 
it oft* from the tree, leaving a space as a hiding-place for the 
caterpillars. Hard cement must be carefully applied by an 
experienced man, otherwise it is likely to prove w-orthless, 
and by crumbling and cracking leave the cavity in a worse 
condition than before. 

This cement cannot be used during the colder months of 
the year, as the action of the frost may cause it to crack. 
Neither can it be used effectively to stop cracks or cavities, 
the sides of which may be moved independently of each 
other by the action of the wind on the branches. Experi- 
ments in closing such cavities with plaster of Paris, mineral 
wool, Purcell's elastic cement, Webster's elastic 
cement, Portland cement and Poslindale cement 
were made in the winter of 1891-92. None of 
these materials gave satisfactory results. Tarred 
burlap or canvas has been used for this purpose 
with some success. If three thicknesses of bur- 
lap are closely and strongly tacked over the 
opening to a hollow in a tree trunk and after- 
fig.,25. Bur. ward thoroughly soaked with coal tar (Fig. 

lapped cavity. ^.^x.i • «n • • . . i • 

25) the covering will remain intact and imper- 
vious to the weather for several vears. Oiled cloth w r ill also 





PLATE XXXIII. Pruning and 



scraping trees. 




COVERING HOLES IN TREES. 189 

answer the same purpose. These fabrics are not materially 
affected by the movements of the tree, and if well tarred are 
not often bored through by insects, as the tar is repugnant 
to them. 

In many cases such cavities as are exposed by the sawing 
off of large hollow stumps of broken branches may be covered 
to advantage with tin or zinc, which must be tacked closely 
over the cavity and afterwards painted or tarred. (See Fig. 
26. ) If these coverings are applied in the win- 
ter, it may be necessary to use in connection with 
them some such substance as the insect lime, in 
order to prevent the escape of the young cater- 
pillars in the spring. This substance may be 
smeared around the edge of the tin or burlap in 
such a manner as to close every crevice commu- 
nicating with the cavity. It has also been used FlG . 26 . 
to stop small holes in trees, and will answer the Tinned cavity> 
purpose temporarily, but it must be occasionally smoothed 
over, as it shrinks and cracks in a short time. 

Scraping Trees and Removing Loosened Bark. 

Scraping the loose outer bark from old trees facilitates 
the discovery of the eggs, larvae and pupa? of the gypsy 
moth. Such scraping leaves the surface of the trunk and 
larger branches in a comparatively smooth condition, and 
deprives the caterpillars of their places of refuge, causing 
them to crawl down and seek shelter under the burlaps. 

If in dealing with fruit trees the loose bark only is scraped 
off and burned, the main object is accomplished. Such scrap- 
ing benefits orchard trees by the removal of mosses and 
lichens and the eggs and hibernating forms of injurious 
insects. 

An implement modelled after the scuffle hoe is useful for 
this work. (Fig. 27. ) Its blade being double-edged, it may 
be used with both the upward and downward motion, and by 
means of a long handle the trunk and branches of the fruit 
trees may be reached to a height of from twelve to eighteen 
feet from the ground. The ordinary "three-cornered" 
scraper is also much used. It is believed that this loose 
outer bark forms a protection to the tree from the cold of 



190 



THE GYPSY MOTH. 



winter. Objections to its removal based on this belief are 
obviated by scraping in the spring before the opening of 
the leaves, when the tree no longer needs protection against 
the cold. If the loose bark of apple trees is scraped off 
about April 15 and caught upon cloths spread beneath the 
trees and the scrapings afterward burned, many injurious 
insects are likely to be destroyed. 





Fig. 27. Long handled Bcraper. 



Fig. 28. Bark shave. 



If we go further, and without cutting too deeply remove 
some of the outer bark, double benefit to the tree ensues.* 

Its growth is stimulated, a great flow of crude sap occurs, 
a luxuriant growth of foliage is thrown out and an unusual 
supply of elaborated sap for the upbuilding of the tree is 
returned from the foliage and flows into the liber or inner 
lining of the bark, killing or driving away the bark borers 
(scolytidce) . These beetles are among the most dangerous 
enemies of trees. For bark cutting a shave (Fig. 28) in- 
vented by Mr. G. W. McKee, one of the special inspectors 
employed by the Board, has been found very effective. 

Dr. Packard says that perhaps the best method of pre- 
venting or stopping the work of bark beetles is that of a 



* Elms which have had the outer bark removed in this manner in November have 
developed an unusually vigorous growth of dark green foliage in the ensuing sum- 
mer. Trees treated in this manner have shown great vigor also in healing wounds 
on their trunks. 



SCRAPING TREES. 191 

Frenchman, M. Robert, as described in the " Gardener's 
Chronicle " and referred to by Miss Ormerod. He gives the 
quotation from Miss Ormerod as follows : — 

The best remedy appears to be that adopted with great success 
in France by M. Robert, after careful observation of the circa in- 
stances which stopped the operations of the female beetle when 
gnawing her gallery for egg laying, or which disagreed with or 
destroyed the maggots, and is based in part on similar observa- 
tions of the effect of flow of sap to those noticed in England by 
Dr. Chapman. 

It appeared on examination that the grubs died if they wei'e not 
well protected from the drying actiou of the air ; on the other 
hand, if there was a very large amount of sap in the vegetable 
tissues that they fed on, this also killed them ; and it was observed 
that when the female was boring through the bark if a flow of sap 
took place she abandoned the spot and went elsewhere. It was 
also noticed that the attack (that is, the boring of the galleries 
which separates much of the bark from the wood) is usually under 
thick old bark, such as that of old elm trunks, rather than under 
the thinner bark of the branches. Working on these observations, 
M. Robert had strips of about two inches wide cut out of the bark 
from the large boughs down the trunk to the ground, and it was 
found that where the young bark pressed forward to heal the 
wound and a vigorous flow of sap took place many of the maggots 
near it were killed, the bark which had not been entirely under- 
mined was consolidated and the health of the tree was improved. 

Working on from this, M. Robert tried the more extended 
treatment of paring off the outer bark, a practice much used in 
Normandy and sometimes in England for restoring vigor of growth 
to bark-bound apple trees, and noted by Andrew Knight as giving 
a great stimulus to vegetation. M. Robert had the whole of the 
rough outer bark removed from the elm (this may be done con- 
veniently by a scraping knife shaped like a spoke shave). This 
operation caused a great flow of sap in the inner lining of the bark 
(the liber), and the grubs of the Scolytus beetle were found in 
almost all cases to perish shortly after. Whether this occurred 
from the altered sap disagreeing with them, or from the greater 
amount of moisture around them, or from the maggots being more 
exposed to atmospheric changes, or any other cause, was not 
ascertained, but the trees that were experimented on were cleared 
of the maggots. The treatment was applied on a large scale, and 
the barked trees were found, after examination by the commis- 
sioners of the institute at two different periods, to be in more 



192 THE GYPSY MOTH. 

vigorous health than the neighboring ones of which the bark was 
untouched. More than two thousand elms were thus treated. 

This account is abridged from the leading article in the " Gar. 
dener's Chronicle and Agricultural Gazette" for April 29, 1848, 
and the method is well worth trying in our public and private 
parks. It is not expensive ; the principle on which it acts as 
regards vegetable growth is a well-known one, and as regards 
insect health it is also well known that a sudden flow of the sap 
that they feed on, or a sudden increase of moisture around them, 
is very productive of unhealthfulness or of fatal diarrhoea to 
vegetable-feeding grubs. 

A somewhat similar process was tried by the Botanic Society, in 
1842, on trees infested by the Scolytus destructor in the belt of 
elms encircling their garden in the Regents' Park, London. " It 
consists in divesting the tree of its rough outer bark, being careful 
at the infested parts to go deep enough to destroy the young larvae, 
and dressing with the usual mixture of lime and cow dung." This 
operation was found very successful, and details with illustrations 
were given in a paper read in 1848 before the Botanic Society.* 

No injury to trees which have been scraped in the course 
of the work on the gypsy moth has been observed, although 
this practice has been continued for three years and more than 
nine thousand trees have been scraped. Apple trees and elm 
trees treated in this way have shown an immediate increase 
of foliage area and growth, presenting a marked contrast to 
trees near by which have been left untreated. Whether a re- 
action will set in in future years remains to be seen. As yet 
no serious reactionary effect has been noted. Trees which 
have been scraped have exhibited remarkable vigor in healing 
wounds. In the gypsy-moth work large elms are frequently 
met with which cannot be cleared of the moth without shav- 
ing off their outer bark. This bark often overgrows small 
cavities in the trunk in such a manner that hiding-places for 
the moth are formed which it is impossible to discover until 
the rougher portion of the outer bark has been removed. 
While that is being done, it is not difficult to expose these 
hiding-places and to destroy any form of the moth found 
within. 

* Fifth report of the United States Entomological Commission, 1886-90, pages 31, 32. 



BURNING RUBBISH HEAPS. 193 

The Destruction of Rubbish. 

The gypsy moth, like many other insects, shows a liking 
for a rubbish pile. Brush heaps, old stone walls and fences 
overgrown with bushes and vines, dumping grounds, old 
piles of lumber, tin cans, rags, paper and other de'bris all 
furnish many hiding-places for the caterpillars, retreats for 
pupating and places where the moth can deposit its eggs. 

It is remarkable how many absolutely filthy rubbish heaps 
accumulate in the back yards of some tenement-houses. 
These deposits of rubbish are especially noticeable in certain 
districts of the larger towns and smaller cities. Not only 
are all sorts of waste material from all parts of the house 
from cellar to garret thrown into the back yard, but refuse 
from the kitchen is also frequently deposited there, together 
with a collection of empty but unclean cans, such as are orig- 
inally used for " canned goods." Old shoes, broken bottles 
and earthen ware, cast-off articles of apparel, corn husks and 
the withered tops of vegetables in all stages of decay, bones, 
fish heads, lobster and oyster shells are also common con- 
stituents of these rubbish piles. Such heaps of rubbish, 
often overgrown with weeds and bushes, would form an in- 
structive spectacle for local boards of health.* Even the 
grounds of the wealthy are not always exempt from accumu- 
lations of rubbish, which may be found occasionally about 
the corners of back fences or in the rear of stables. 

Amid such associations the gypsy moth delights to dwell. 
In the many places of shelter offered by such rubbish heaps 
the larvae can safely hide during the day, sallying forth at 
dusk to destroy the foliage in the vicinity. 

One of the first steps, then, toward exterminating the 
gypsy moth from any locality is to clear up the ground; 
burn rubbish, old lumber, wood, brush, rags and dead leaves ; 
bury or melt up old tin cans ; tear down or remove stone 
walls and old fences ; and leave the premises as clean as pos- 
sible. Cremation is a cleansing process ; bonfires mark the 
progress of civilization. Such work will not only aid in 



* There has been much improvement in respect to the accumulation of rubbish in 
yards in our cities and large towns since the slight cholera scare of 1893. 



194 



THE GYPSY MOTH. 



disposing of the moth but will remove harboring places 
for other insects and render the locality more healthful and 
wholesome. The agents of the Board of Agriculture have 
found it necessary to remove, burn or bury many of these 
accumulations of debris in order to secure the destruction of 
the moth. 

Destroying Pupae and Mollis. 

As the eggs of the gypsy moth hatch in the months of 
April, May and June, the larvse feed in the latter part 
of April and during the months of May, June, July and 
August. In July and August all forms of the moth may 
be found together in the same locality. Pupa? and moths 
are found upon the same trees, under the same burlaps and 
in the same rubbish heaps with the larvse ; therefore no 
special measures are taken to destroy these forms of the 
insect. They are searched for in all the hiding-places which 
shelter caterpillars, and are destroyed by the same means. 
The white female imagoes are especially noticeable when 
resting on the bark of trees. They may be found in July 
and August, and, as they do not fly, they may be readily 
captured. 



A Summary of the Methods most Useful to the 

Farmer. 

Unless sufficient appropriations are made to exterminate 
the gypsy moth or to hold it in check where it now is, its 
rapid increase and spread over this and other States will 
probably follow. In case of the permanent cessation of 
public exterminative or preventive work, the labor of hold- 
ing the gypsy moth in check or of repressing its destruc- 
tive outbreaks will devolve upon the citizen and especially 
upon the farmer. 

In considering the methods most useful to the farmer for 
the destruction of the gypsy moth, it is well to inquire, first, 
what class of farming crops are most liable to injury by the 
pest. As the gypsy moth feeds by preference on trees, shrubs 
and foliaceous plants, those farmers who devote themselves 
entirely to dairying or grain raising will be likely to suffer 
least. Market-gardeners have less to fear from the gypsy 



METHODS FOR THE FARMER. 195 

moth than the general farmer or fruit grower. The well-to- 
do market-gardener who raises little or no fruit has few trees 
on his land to care for ; his methods of cultivation are inten- 
sive, and he is obliged to employ a number of field hands 
in his business. He is therefore better able to protect his 
crops against the attacks of an insect like the gypsy moth 
than is the general farmer or the small farmer who has to 
depend largely on his own labor. There would be less 
danger to the interests of the agriculturist in thickly settled 
districts where market-gardening is carried on than in thinly 
settled sections where farms are larger and less highly culti- 
vated, where much wood is grown and where there are many 
orchards. In such regions the waste and wooded land, where 
the moth might breed and where little could be done by the 
owners to check it, greatly exceed in area the cultivated 
land, where its ravages would do the greatest injury. 

In considering, then, the means most useful to the farmer 
for controlling or exterminating the moth, we must choose 
those most readily available to the general farmer of moder- 
ate means. 

Burning the eggs or killing them by means of creosote or 
other oils are the methods which can be used most effectually 
by most farmers. The work can be done during the late 
fall, winter and early spring, —a time of the year when 
most farmers are not overburdened with the labors and cares 
incidental to planting and harvesting. If this is thoroughly 
done in an orchard, there need be no fear of the fruit crop 
being destroyed in the ensuing summer by the gypsy moth 
unless the orchard is invaded from without by caterpillars 
which have bred in the woods or upon shade trees. 

If shade trees are near the orchard, all the orchard trees 
cleared of eggs should be banded with insect lime or supplied 
with tree protectors, either of which will go far toward 
protecting them from the inroads of migrating caterpillars. 
But if there is a tract of badly infested woodland near the 
orchard, the bands will be of little use in protecting the 
trees against the invasion of the multitude of caterpillars. 
In such cases the most economical plan would be to cut 
down all the infested woods and burn over the ground. Few 
farmers can afford to attempt to keep the pest out of wood- 



196 THE GYPSY MOTH. 

land, as the cost of the labor would be more than the value 
of the wood. If precautionary measures have been neg- 
lected, and the caterpillars appear in swarms, they may strip 
the trees before arriving at an age when they will seek the 
burlap. 

When small caterpillars are very numerous upon the trees, 
spraying with arsenate of lead at the rate of thirty pounds 
to one hundred and fifty gallons of water will destroy most 
of them. If arsenate of lead is not at hand, two or three good 
sprayings with Paris green in May will greatly lessen their 
numbers. The trees may be afterwards burlapped, and the 
caterpillars killed as they gather day by day under the bur- 
laps. A small burning tank with a cyclone burner might be 
used to stay the march of an invading host of these cater- 
pillars, and would check them anywhere. (See Plate XX.) 
The care of trees and the general cleanliness of grounds will 
do much toward rendering an orchard an unfit dwelling-place 
for the gypsy moth, and will facilitate the moth's destruction. 

The Annual Inspection. 

The inspection and egg-killing in the infested district and 
the inspection in the towns in its vicinity during the late fall, 
winter and early spring are the chief means of preventing 
the dissemination of the moth, and the first and most impor- 
tant steps toward extermination. It is by examining the 
trunks and the lower surfaces of large limbs of trees during: 
this search that most of the conspicuous egg-clusters are 
found. In this way most of the colonies of the moth have 
been discovered.* It is for the prosecution of this work 
that the most efficient and experienced men are retained. 
The inspection goes on through the winter months, except 
when interrupted by severe storms, deep snow or the ex- 
haustion of the appropriation. 

So long as there are moths in the district at present in- 
fested, just so long will there be danger of their distribution 
throughout that district and to adjacent towns ; the danger 



* Webster defines a colony (under the head of natural history) as a number of 
animals or plants living together beyond their usual range. In the gypsy-moth work 
the word " colony " has been applied to the moth when it has been found isolated 
from others of its kind by a belt of uninfested country. 



THE ANNUAL INSPECTION. 197 

increasing or decreasing, according to the increase or reduc- 
tion of the number of the moths, especially along highways 
or in cultivated lands and woodlands most frequented by 
man. 

Each autumn, as soon as the foliage is well off the trees, 
the most experienced employees of the Board are organized 
into squads, which are set to work examining such territory 
within the infested towns as has not been recently inspected. 
Many colonies have thus been found by careful search within 
the region known in 1891 to be infested. Much time and 
money have been spent in this search, but money enough 
has not been provided in any year to make the search 
thorough and complete. To provide against the spread of 
the moth, more or less of this kind of work has been done 
each year in the towns outside of the infested region. In 
this outside search considerable time and money have been 
expended, and only a few small colonies of the moth have 
been found. These were all at a short distance outside 
the boundary of the region known in 1891 to be infested. 
Though this search does not at first sight appear to have 
furnished results proportionate to the expense incurred, yet, 
had the colonies not been found and stamped out of exist- 
ence, any one of them might have increased and spread 
like the original Trouvelot colony. 

As the prevention of the spread of the moth and its exter- 
mination are the objects contemplated by the statute author- 
izing the work, this search of towns adjacent to the infested 
region must continue so long as the region continues to be 
infested; otherwise, there can be no absolute assurance that 
the moths are not spreading beyond the limits of the region 
in which the work is carried on. 

As the search extends farther away from the centre of the 
infested region, the territory to be examined becomes greater, 
increasing the expense, while the likelihood of its being in- 
fested diminishes. Therefore, in towns next outside those 
immediately adjacent to the infested region the search is 
confined to those places which experience has shown are 
most likely to become infested, mainly the villages and bor- 
ders of highways. Especial attention is paid to all points 
which by reason of the character of the business of the resi- 



198 



THE GYPSY MOTH. 



dents appear to have been particularly exposed to infesta- 
tion. 

Beyond these towns only the borders of railways, certain 
highways, the centres of villages and such estates as are 
believed to have been exposed to a possibility of infestation 
are inspected. A few cities which are centres of trade and 
travel form an exception to this rule. They have been more 
thoroughly inspected. The following cities and towns have 
been more or less thoroughly looked over. Some have been 
visited only once, but most of them have been inspected 
several times during the last five years. In none of them 
has any trace of the moth been found : — 



Bedford. 


Ipswich. 


North Andover. 


Boxford. 


Lincoln. 


Quincy. 


Billerica. 


Lowell. 


Rowley. 


Brookline. 


Middleton. 


Sudbury. 


Concord. 


Manchester. 


Topsfield. 


Dedhani. 


Milton. 


Tewksbury. 


Essex. 


Newton. 


Wilmington. 


Georgetown. 


Newbury. 


Wayland. 


Gloucester. 


Newburyport. 


Weston. 


Hamilton. 


North Reading. 


Wenham. 


Hull. 







Measures for the Information of the Public. 
The Board of Agriculture has from the first believed that 
success in the work of preventing the spread and securing 
the extermination of the gypsy moth could not be hoped for 
without the intelligent co-operation of the public. Every 
effort, consistent with the letter and meaning of the statute 
under which the work has been carried on, has been made 
to diffuse information in regard to the identity and character 
of the pest and the laws enacted and regulations made for 
its destruction. The rules and regulations of the gypsy 
moth committee have been frequently advertised in the daily 
papers. Every facility has been offered to the daily and 
weekly press in regard to the publication of illustrated arti- 
cles upon the gypsy moth. Cuts of the moth have been 
loaned many newspapers, and have had a wide circulation. 
Information has been frequently given to the agricultural 
press. 



DISTRIBUTING INFORMATION. 199 

The prejudice existing against the spraying and other feat- 
ures of the work, which was expressed in the local press 
in 1890, continued to find some expression in 1891. The 
papers, however, gave the work of the Board of Agriculture 
a wide publicity. We can do no less than acknowledge the 
spirit of fairness of the press of the State, and the willing- 
ness manifested to publish everything in regard to the work 
which would be of interest to the people. Yet false reports 
as to the appearance of the gypsy moth in various places at 
a distance from the infested region have been frequently and 
widely circulated. These appear to originate not with the 
newspapers themselves but with citizens who, believing that 
they have discovered the gypsy moth on their premises, can- 
not wait to notify the Board, but immediately rush into print 
and so give the alarm. In all such cases it has been found 
upon investigation that the injury noticed was caused by some 
other insect. Yet these local ' ' scares " have assisted in arous- 
ing the interest of the people, and leading them to further 
investigation of the appearance and character of the moth. 

Early in 1891 arrangements were made with an artist for 
drawings of the gypsy moth to be reproduced for illustra- 
tion. A colored plate (Plate I. of this report) was prepared 
and printed in the first annual report of the State Board 
of Agriculture on the extermination of the gypsy moth. 
Ten thousand copies of this report were printed and dis- 
tributed throughout the Commonwealth, especially in and 
near the infested district. Fifteen hundred extra copies 
of the plate were also printed, to be used in connection 
with other material and for posting in public places, such 
as post-offices, schools, libraries and museums. One hun- 
dred and fifty glass-covered cases, containing specimens 
of the different forms of the gypsy moth, preserved, mounted 
and labelled, were prepared for exhibition in the infested 
district, as well as for museums and other public places in 
the State. A bulletin of information was also prepared, and 
five hundred copies were printed in large type and framed. 
In the centre of each frame was placed one of the colored 
plates representing the different forms of the gypsy moth ; a 
printed explanation accompanied the plate. These frames 
were placed in prominent positions in post-offices, mostly 



200 THE GYPSY MOTH. 

in eastern Massachusetts. A large frame containing in addi- 
tion to the bulletin a photograph of the moth's ravages, and 
having a specimen case attached, was placed in the main post- 
office of each city or town in the infested district. 

In 1891 a bulletin of information in regard to spraying for 
the gypsy moth and other insects was printed in pamphlet 
form and distributed through the infested district. Some 
fifty thousand copies of the law of 1891, providing for the 
extermination of the gypsy moth, together with the rules and 
regulations under which the work is conducted, have been 
printed and distributed among the people of the infested 
district and in towns near by. The law and the rules and 
regulations were also printed in poster form and posted in 
many public places. Many placards containing certain sec- 
tions of the law were also printed and posted. Each season 
from twenty thousand to twenty-five thousand copies of the 
annual report on the gypsy moth (each with a colored plate 
of the insect) have been printed for distribution, in addition 
to the nine hundred copies annually printed for the use of the 
Legislature. Circular letters, calling the attention of citizens 
to the threatening danger from the invasion of the moth, 
have been printed and sent with or without the reports to 
newspapers and citizens throughout the State. Lectures on 
the gypsy moth and the means of its extermination have been 
given by the secretary of the Board of Agriculture, the ento- 
mologist and the director. Other speakers have frequently 
spoken on the same subject at farmers' institutes and other 
meetings. 

When the Massachusetts exhibit at the World's Columbian 
Exposition at Chicago was being prepared, the committee 
in charge requested the Board of Agriculture to prepare an 
exhibit for the exposition. This was done, and the exhibit 
occupied a central place in the Massachusetts building at the 
fair. It consisted of a glass case seven feet in height, contain- 
ing a representation of an apple tree denuded of its leaves 
by the gypsy-moth caterpillars, and exhibiting on its trunk 
and branches all forms of the moth, together with many of 
the vertebrate and invertebrate enemies of the moth, includ- 
ing birds, fowls, predaceous beetles and parasites. Pho- 
tographs showing the destructiveness of the moth were 



FALSE ALARMS. 



201 



exhibited. A large amount of printed matter in regard to 
the moth was distributed at the fair. 

In October, 1895, in response to a request received from 
the Massachusetts Charitable Mechanic Association, this ex- 
hibit was sent to the fair held in the Mechanics building, 
Boston, where it was exhibited together with another case 
containing sections of tree trunks and other objects on which 
the egg-clusters of the gypsy moth had been laid. There was 
also a collection of bromide enlargements of photographs, 
showing the moth as in nature, its ravages and the means of 
destroying it. At the request of L. O. Howard, entomolo- 
gist of the United States Department of Agriculture, dupli- 
cates of some of these bromides were also sent to the Cotton 
States and International Exposition at Atlanta, Ga., where 
they were exhibited as a part of the entomological exhibit of 
the United States Department of Agriculture. 

The measures taken to inform the public have succeeded 
in arousing public interest to such an extent that many 
citizens of the State immediately report to the Board any 
injurious insects which appear to them to be gypsy moths. 
Such reports are sometimes received from other States. 
Many false alarms of the moth's presence have been sent in, 
and all have been investigated. Reports of the appearance 
of insects which were wrongly supposed to be the gypsy 
moth have been received from the following places : — 



Places from 


which False Alarms 


have been received. 


Massachusetts. 


Brockton. 


Georgetown 


Acton. 


Brookfield. 


Gloucester. 


Andover. 


Bourne. 


Grafton. 


Ashburnham. 


Chester. 


Groton. 


Athol. 


Concord. 


Hold en. 


Abington. 


Charlton. 


Hopedale. 


Amesbury. 


Carlisle. 


Haverhill. 


Auburn. 


Clinton. 


Holliston. 


Billerica. 


Dedham. 


Hyde Park. 


Berlin. 


Duxbury. 


Hingham. 


Braintree. 


Easton. 


Hudson. 


Bedford 


Fall River. 


Hull. 


Bolton. 


Foxborough. 


Ipswich. 


Boxford. 


Fitchburg. 


Lincoln. 


Brookline. 


Framingham. 


Lowell. 


Bridgewater. 


Gill. 


Lawrence. 



202 



THE GYPSY MOTH. 



Places from which False 

Massachusetts — Con. 
Marlborough. 
Marshfield. 
Merrimac. 
Milford. 
Methuen. 
Manchester. 
Maynard. 
Milton. 
Monson. 
Newburyport. 
Newton. 
Needham. 
Newbury. 
Northbridge. 
Norwood. 
North Andover. 
North Brookfield. 
North Reading. 
Pittsfield. 
Pepperell. 
Plymouth. 
Princeton. 
Quincy. 
Randolph. 
Rowley. 
Rockport. 



Alarms have been received — Concluded. 



Rehoboth. 

Scituate 

Southborough. 

Sterling. 

Sutton. 

Sudbury. 

Springfield. 

Templeton. 

Tewksbury. 

Townsend. 

Tyngsborough . 

Uxbridge. 

Weymouth. 

Wenham. 

West Bridgewater. 

Wilmington. 

Weston. 

Westborough. 

West Newbury. 

Wellesley. 

Wayland. 

Wrentham. 

Worcester. 

Rhode Island. 
Providence. 
Pawtucket. 



Connecticut. 
Fairfield. 
Glastonbury. 
Ridgefield. 

Maine. 
Cape Porpoise. 
Sabbatus. 

New Hampshire. 
Barnstead . 
Center Harbor 
Haverhill. 
Kensington. 
Kingston 
Lakeport. 
Portsmouth. 
Pratts. 
Seabrook. 

Iowa. 
Fort Madison. 

Vermont. 
Green River. 



In all cases the damage reported was caused by some 
other insect. The many reports thus received are gratify- 
ing, indicating as they do a public interest in the work, 
and a desire to aid as far as possible in stamping out the 
pest. The investigations in other States have been made 
mainly to prove or disprove the claim that the gypsy moth 
is confined in America to a limited district in Massachusetts. 
This is the theory on which the work of extermination has 
so far proceeded, and no proof has ever been given that it 
has been found outside of this district. 





• ^^^^1 


$ff! tf 10' iJflP 




gPE! 








% 

I 

•1 






I 






.j-U?^/^ 




.. 



PLATE XXXV. Baltimore orioles and nest. 



NATURAL ENEMIES. 203 



Natural Enemies of the Gypsy Moth. 

Insect-eating Birds. 
Since the work of preventing the spreading and securing 
the extermination of the gypsy moth in Massachusetts was 
placed in the hands of the Board of Agriculture in 1891, 
particular attention has been paid to the natural enemies of 
the moth. All persons employed in the work have been 
instructed to watch for enemies or parasites, and keep a 
record of all observations made. In accordance with these 
instructions, voluminous notes now covering many hundred 
pages have been made. Many enemies of the moth have 
been studied both under natural conditions and in confine- 
ment. Search has been made through European literature 
for information in regard to the enemies of the moth abroad. 
Much information bearing upon the subject has also been 
obtained by foreign correspondence. In apportioning the 
preparation of the report on the natural enemies, the task of 
preparing a report on the birds was assigned to me. My 
colleague, Professor Fernald, will treat of tlie other enemies 
of the moth. 

The Usefulness of Birds as Insect Destroyer's. 

The subject of birds versus insects is a most important 
one. The influence of birds on the agriculture of a country 
is incalculable. The protection or destruction of native birds 
and the introduction of foreign species are subjects worthy 
of the most thoughtful consideration of the agricultural 
department of any government. 

Land birds fulfil their part in many ways in preserving 
the balance of nature, but chiefly by doing much toward 
holding in check the increase of the insect world, which, if 
unrestricted, would swarm over and devastate the earth. 

Birds are among the most highly organized of vertebrate 
animals. In them we find the greatest activity and the 
highest temperature of the blood. To maintain this tern- 



204 THE GYPSY MOTH. 

perature and supply the tremendous waste of the tissues 
caused by this activity a great quantity of food is necessary. 
Excellent provision is made by nature for the rapid digestion 
and assimilation of a great amount of food. In August, 
1895, two young crows were confined at the experiment 
station in Maiden, and observations were made on their feed- 
ing habits. The time from the entrance of the food into the 
mouth to the first voiding of excreta containing remains of 
the food eaten was usually about one and one-half hours. It 
is probable that digestion is still more rapid in the smaller 
insect-eating birds.* The common titmouse or chickadee 
(Parus atricapillus) is one of the smaller birds of New Eng- 
land, yet the good accomplished by it in destroying the eggs 
of insects injurious to orchard and forest trees is almost 
beyond belief. I have given elsewhere an estimate, based 
on careful observations and dissections, that in twenty-five 
days one of these birds will destroy 138,750 eggs of the 
canker-worm moth (Anisopteryx pometaria) .f 

Prof. Samuel Aughey, who fed confined plovers on in- 
sects, found that they would eat on an average 202 locusts 
and other large insects per day .J 

Professor Treadwell fed to a young robin in twelve hours 
forty-one per cent, more than its own weight in worms. The 
same bird consumed nearly half its own weight of beef in a 
day.§ 

At this rate a man would eat daily about seventy pounds 
of meat. Because of their enormous appetites, birds are 
most potent factors for good or ill. It is well known that 
crows and blackbirds destroy vast quantities of grain for a 
short season when they swarm upon the fields ; but their 
services in destroying injurious insects are not generally 
recognized. 

* According to Maynard the indigestible remains of food are excreted by the cedar- 
bird in one-half hour after eating. (See " Birds of Eastern North America," C. J. 
Maynard.) 

t Bulletin on "Birds as protectors of orchards," Massachusetts Crop Report, 
July, 1895, published by the Massachusetts State Board of Agriculture. 

% First report United States Entomological Commission, 1877, page 343. 

§ "Birds of New England," by E. A. Samuels, page 159. The paper on this 
subject was originally read by Professor Treadwell before the Boston Society of 
Natural History. 



USEFULNESS OF BIRDS. 205 

The activity of birds, as shown in running, climbing trees, 
hopping or flying, together with their powers of vision, 
renders them particularly adapted for searching out, over- 
taking and destroying insects. Birds often assemble where 
insect outbreaks occur, and assist in checking great insect 
invasions. 

In a search through agricultural, entomological and orni- 
thological literature, we find many instances on record in 
both hemispheres where birds have been instrumental in 
saving crops or forests by destroying injurious insects. 
Samuels states that in 1847, as an immense forest in Pom- 
erania was on the brink of being utterly ruined by caterpil- 
lars, it was suddenly and very unexpectedly saved by a flock 
of cuckoos, who established themselves in the place for a 
few weeks and thoroughly cleaned each tree.* 

During the great locust invasions in the West the investi- 
gations of Professor Aughey, as published in the first report 
of the United States Entomological Commission, showed 
that birds were among the greatest enemies of locusts, and 
that in many instances when the farmers had given up the 
battle against the "grasshoppers," the crops were saved by 
the flocks of birds that descended upon the fields, destroying 
immense numbers of the feeding locusts. f 

Many instances are on record where a great increase of 
insect pests has followed the destruction of birds. George 
Kearly, in the "Entomologist's Weekly Intelligencer," 
speaks of an outbreak of insect pests in a park at Brussels, 
in which the gypsy moth was one of the chief offenders, hav- 
ing stripped well-nigh all the trees of their foliage. He says 
this great increase of insects followed soon after and was 
caused by the destruction of sparrows and other birds in the 
park, by order of the authorities.^ In a letter recently 
received from J. O. Clercy, secretary of the Society of 
Natural Sciences, Ekaterinburg, Russia, he states that the 
ravages of two species of cutworms and some ten species 



* E. A. Samuels, in report of Massachusetts State Board of Agriculture, 1865-66, 
page 117. 
t Report of the United States Entomological Commission, 1877, page 338. 
X The "Entomologist's Weekly Intelligencer," 1858, Vol. 4, page 192. 



206 THE GYPSY MOTH. 

of locusts contributed, together with the want of rain, to 
starve the inhabitants in that region in 1891 and 1892. 
One of the causes, he says, which permitted such a numer- 
ous propagation of insect pests was the almost complete de- 
struction of birds, most of them having been killed and 
sent abroad by wagon loads for ladies' hats. A law for the 
protection of birds has now been enacted, and, says Clercy, 
"the poor little creatures are doing their best to reoccupy 
their old places in our woods and gardens. This inoccu- 
pation, however, does not go on as rapidly as did their 
destruction." 

Many species of water birds, the gulls and terns especially, 
are useful as insect destroyers. In 1848 the crops of the 
Mormons in Utah were attacked by the Western cricket (Ana- 
brus simplex), which came down in great armies from the 
highlands about Salt Lake. These crickets had already 
destroyed a considerable portion of the crops, when great 
flocks of gulls appeared and ate the crickets. Hon. George 
Q. Cannon says: "Black crickets came down by millions 
and destroyed our grain crops ; promising fields of wheat 
in the morning were by evening as smooth as a man's hand, 
— devoured by the crickets. Sea gulls came by hundreds 
and thousands, and, before the crops were entirely destroyed, 
these gulls devoured the insects so that our fields were 
entirely freed from them." * 

This occurrence is well authenticated and testified to by 
many eye-witnesses, f 

While some ornithologists regard birds as by far the most 
important natural enemies of injurious insects, many ento- 
mologists believe that insect and vegetable parasites are more 
useful in this respect than birds ; yet some of the most 
eminent economic entomologists, who have had occasion to 
observe the insect-eating habits of birds in connection with 
great outbreaks of insect pests, have been among the first to 



* " Insect Life," Vol. 7, No. 3, page 275. 

t See the nineteenth annual report of the secretary of the Massachusetts Board 
of Agriculture, 1871, page 76; the report of the United States Commissioner of Ag- 
riculture, 1871, page 79; also the second report of the United States Entomological 
Commission for 1878 and 1879, relating to the Rocky Mountain locust, page 166, 
A. S. Packard, Jr. 



MOTH-EATING BIRDS. 



207 



give public expression to their appreciation of the value of 
birds as destroyers of noxious insects.* 

A study of the food of insect-eating birds leads to the belief 
that if in any way their numbers and efficiency can be aug- 
mented, an increase in agricultural products will be secured. 

Birds seen -to feed upon the Gypsy Moth. 
Thirty-eight species of birds have been identified when 
feeding upon the gypsy moth in one or more of its forms. 
They are as follows : — 



Yellow-billed cuckoo, 
Black-billed cuckoo, 
Hairy woodpecker, 
Downy woodpecker, 
Pigeon woodpecker, 
King bird, 

Great-crested flycatcher 
Phoebe, . 
Wood pewee, 
Least flycatcher, . 
Blue jay, 
Crow, . 

Baltimore oriole, . 
Purple grackle or crow 
Chipping sparrow, 
Chewink, 

Rose-breasted grosbeak- 
Indigo bird, . 
Scarlet tanager, . 
Red-eyed vireo, 



. Coccyzus americanus. (Linn.) 

. Coccyzus erythropkthalmus. (Wils.) 

. Dryobaies villosus. (Linn.) 

. Dryobates pubescens. (Linn.) 

. Colaptes auratus. (Linn.) 

i . Tyrannus tyrannus. (Linn.) 

. Myiarchus crinitus. (Linn.) 

. Sayornis phcebe. (Lath ) 

. Contojnis virens. (Linn.) 

. Empidonax minimus. Baird. 

. Cyanocilta cristata. (Linn.) 

. Corvus americanus. And. 

. Icterus galbula. (Linn.) 

blackbird, Quiscalus quiscula. (Linn.) 

. Spizella socialis. (Wils.) 

. Pipilo erythrophthalmus. (Linn.) 

. Habia ludovlciana. (Linn ) 

. Passerina cyanea. (Linn.) 

. Piranga erythromelas. Vieill. 
Vireo olivaceus. (Linn.) 



* Townend Glover, first entomologist of the United States Department of Agri- 
culture, wrote in 1871 : " Insectivorous birds are the best allies of the farmer, and 
were they all destroyed there is little doubt that it would be almost impossible to 
raise certain crops." (Report of the United States Commissioner of Agriculture, 
1871, page 71.) 

He also wrote : " A knowledge of their nature and habits is of as much impor- 
tance to the farmer and fruit culturist as is the science of entomology." (Report of 
the United States Commissioner of Agriculture, 1865, page 36.) 

Prof. C. V. Riley, late entomologist of the Department of Agriculture, has testified 
to the utility of birds as follows : " Few injurious insects can be well and fully 
considered without reference to their liability to be devoured by various natural 
enemies, and especially birds." (Report of the United States Commissioner of 
Agriculture, 1885, page 210.) 

Prof. John B. Smith, State entomologist of New Jersey, in an address to the 
farmers of New Jersey, said: "Take care of your natural friends! Among these 
the birds rank highest." ("Insecticides, and how to apply them," seventeenth 
annual report of the New Jersey State Board of Agriculture, 1889-90, pages 294, 295.) 



208 



THE GYPSY MOTH. 



Yellow-throated vireo, . 
White-eyed vireo, 
Black-and-white warbler, 
Yellow warbler, .... 
Chestnut-sided warbler, 
Black-throated green warbler, 
Oven bird, ..... 
Maryland yellow-throated war- 
bler, 

American redstart, 

Catbird, 

Brown thrasher, . 

House wren, 

White-breasted nuthatch, 

Chickadee, 

Wood thrush, . 
American robin, . 

Bluebird, 

English sparrow, . . . . 



Vireo flavifrons. Vieill. 
Vireo noveboracensis. (Gmel.) 
Mniotilta varia. (Linn.) 
Dcndroica cestira. (Gmel.) 
Dendroica pensyliMn ica. (Linn.") 
Dendroica vircns. (Gmel.) 
Seiurus aurocapillus. (Linn.) 

Qeothlypis Irichas. (Linn.) 
Seto])haga rutieilla. (Linn.) 
Oaleoscoples carolinensis. (Linn.) 
Harporhynchus rufus. (Linn.) 
Troglodytes cedon. Vieill. 
Siita carolinensis. Lath. 
Partes atricapillus. Linn. 
Tardus mustelinus. Gmel. 
Merula migratoria. (Linn.) 
Sialia sialis. (Linn.) 
Passer domesticus. (Linn.) 



Birds which feed on the Larvae , Pupae and Imagoes. 

It is generally believed by entomologists (judging from 
their writings) that hairy caterpillars have a certain immu- 
nity from the attacks of birds. In Europe this appears to 
be true to some extent of the larvae of the gypsy moth. A 
writer in the " Annales de FInstitut Horticole de Fromont" 
says that in twenty years of observation he has not seen a 
bird bring one of the caterpillars to its young.* 

Keppen, writing of the gypsy moth in Eussia, says that 
the cuckoo is the only bird which takes them. Grimm 
noticed about Saratov that birds had completely forsaken the 
places where the caterpillars were usually numerous. This 
is said to have taken place also in the district of Kirsanov in 
the province of Tambov, f Grimm thinks this is owing to 



* "Annales de l'lnstitut Horticole de Fromont," Vol. 5, page 311, Paris, 1833. 

t This does not agree with the experience of the forest authorities in Bavaria 
during the recent invasion occasioned by the spruce moth or " nun " (Liparis 
monaeha), 1889-91. This insect is closely allied to the gypsy moth and was 
formerly placed in the same genus. The caterpillars are provided with hairs sim- 
ilar to those of the gypsy caterpillars. The flight of starlings collected in one 
locality alone was credibly estimated at 10,000, all busy feeding on the caterpillars, 
chrysalides and moths, not to mention enormous flights of titmice and finches sim- 
ilarly engaged. The attraction of starlings to such centres became so great that 
market-gardeners felt their absence seriously in distant parts of the country. 

" Protection of Woodlands," by Hermann Farst, English edition; translated by 
John Nisbet, 1893, page 126. 



OBSERVATIONS ON BIRDS. 209 

the fact that the body of the caterpillar is covered with small 
hairs, which become detached, and, piercing somewhat the 
skin of persons and animals, cause great itching.* 

I have found very little evidence in the writings of Euro- 
pean authors that birds other than the cuckoo and the tit- 
mice destroy the larvae of the gypsy moth, although several 
species are said to destroy the eggs.f In this country, how- 
ever, the reverse appears to be true. Few birds seem to 
eat the eggs, while many attack all other forms of the moth. 
In the season of 1891 my attention was first called to the fact 
that certain birds were devouring large numbers of the larvae. 
The accuracy of the reports received was soon verified by 
my own observations. Several species of birds were seen 
busily engaged in eating the insects wherever they were 
numerous. The inspectors were directed to record all 
observations made on birds which were feeding on the cater- 
pillars. 

Unfortunately, there were at that time only eleven observ- 
ers on the force who could accurately identify birds in the 
field. These men were also perfectly familiar with the dif- 
ferent forms of the moth. The notes made by them indi- 
cated that thirteen species of birds were feeding on the 
moth in one or more of its forms. The observations begun 
in 1891 have been continued during a part of each succeed- 
ing summer. Although as a rule they have been made inci- 
dentally in connection with the work in the field, one or 
more men have been detailed at times to disprove or confirm 
reports that have been made, or to watch some particular 
species of bird, so that some points in regard to its value as 
a moth destroyer might be settled. Where the caterpillars 
are very numerous, they cluster in masses on trees. Cer- 
tain birds habitually visit these swarms either to eat the 
caterpillars or to take them as food to their young. If the 
observer remained quietly at his post, he was able to view 
them at a distance of a few feet or yards. Each observer was 



* Translated from " Injurious Insects " by Theodore Keppen, 3d Vol., special 
part. 

t In a recent letter Dr. Ebermayer of Munich names starlings, crows, titmice and 
tree creepers among the enemies of the gypsy moth but does not say what form of 
the moth they destroy. 



210 THE GYPSY MOTH. 

supplied with an opera glass, by means of which he could 
determine at a greater distance whether or not the birds were 
feeding on the caterpillars of the gypsy moth. Few birds 
were shot and few dissections made as compared with the 
number of birds reported as feeding on the caterpillars. 
This might serve to discredit the accuracy of the observa- 
tions, were they not made at close range, and when the 
caterpillars were large enough to be readily identified. No 
birds were shot except where it was absolutely necessary to 
determine whether it was the gypsy moth caterpillar or 
some other upon which they were feeding. No observations 
were accepted as conclusive unless the observer was known 
to be careful in his work and conservative in his statements, 
or unless ample corroborative evidence was obtained. While 
there is some possibility of error in field observations, there 
is also a possibility of error in stomach examinations. Di- 
gestion in birds is so rapid that it is impossible to specifi- 
cally identify some portions of their insect food unless the 
bird is killed within a very few minutes after the insects are 
eaten. When birds are feeding on larvoe, a large proportion 
of the stomach contents is often unrecognizable.* 

Birds do not always swallow hairy caterpillars whole. In 
many cases they tear them open, eating only some of the 
internal parts which are unrecognizable upon dissection of 
the stomach. Other birds appear to kill wantonly many 
caterpillars and moths. Woodpeckers, jays and chickadees 
have been seen to snap them up and then drop them to the 
ground, sometimes uninjured but often mortally hurt. 
Sparrows and other birds have been seen to kill many moths 
which they do not eat. 

The Most Useful Birds. 
The records of the observations made on birds comprise 
one hundred and fifty typewritten pages. A glance over 
these pages shows that the greater number of observations 
have been made on less than a dozen species, and indicates 
that these are probably the birds most useful in destroying 

* Considering the possibility of error in records made from either observation or 
dissection, it would seem that one should be used as a supplement to and a check, 
on the other. 



MOST USEFUL BIRDS. 



211 



the gypsy moth. It cannot be stated with certainty which 
species is of most value in this respect, as the birds ob- 
served vary both in numbers and usefulness with the locality 
and season. From observations made eleven species are 
known to be very useful. In the apparent order of their use- 
fulness they are : yellow-billed cuckoo, black-billed cuckoo, 
Baltimore oriole, catbird, chickadee, blue jay, chipping spar- 
row, robin, red-eyed vireo, yellow-throated vireo and crow. 




Fig. 29. Yellow-billed cuckoo. 



The cuckoo is the only bird that I have found mentioned 
in European literature as feeding commonly on the larvae 
of the gypsy moth. Altum says the cuckoo is efficient 
especially in local ravages of the moth.* Appearances in- 
dicate that the cuckoos lead the rest of the American birds 
in destroying the gypsy moth. Yet it must be considered 
that as these cuckoos are comparatively large birds, seeking 
by preference the larger larva?, their feeding is readily ob- 
served. As the larvae are usually swallowed whole by the 
cuckoo, their remains are readily recognized in the dissected 
stomach. It is difficult to identify with certainty the smaller 
larvae when they are eaten by small birds. If these small 
birds consume the smaller larvae in numbers equal to those 
of the larger ones eaten by the cuckoo, they are more benefi- 
cial, as the destruction of the larvae when young will prevent 
the injury they might do to vegetation before the cuckoo 
would be likely to attack them. 



* " Forstzoologie," Vol. III., page 96. 



212 THE GYPSY MOTH. 

Yellow-billed Cuckoo. — In 1891 yellow-billed cuckoos 
were observed in several of the worst infested localities, 
where they remained nearly all day, feeding on the gypsy 
larvae or carrying them from time to time to their young. . 
This habit of feeding on hairy larvae seems to be quite con- 
stant with the cuckoos. They seem to prefer the gypsy 
larvae even to the pupae. 

Mr. F. H. Mosher, an inspector in the employ of the 
Board, wdio observed this species in 1895, says that it will 
go to a bunch of pupae and search for larvae, pulling out the 
molts or casts, and will take pupae only when larvae are not 
to be found. This was noticed in different individuals of 
this species and in different localities. Some of the cuckoos 
would take no pupae at all, but would continue their search 
for larvae until they found them. 

That the yellow-billed cuckoos feed their young quite con- 
stantly on these larvae is evident from the observations made. 
The stomach of one young cuckoo when examined contained 
a number of partly digested larvae and the heads of sixteen 
others. Ninety per cent, of the stomach contents consisted 
of these larval remains. When the young birds were able to 
fly, the parents would lead them to the worst infested spots 
and feed them frequently with caterpillars. 

Mr. C. E. Bailey, an agent of the Board and a field orni- 
thologist of much experience, says that the yellow-billed 
cuckoo is very fond of the gypsy larvae, sometimes eating 
nine or ten full-grown ones in less than a half hour. He 
also states that he has observed that it eats more caterpillars 
than the black-billed cuckoo. 

Black-billed Cuckoo. — The black-billed cuckoo is probably 
nearly if not quite as useful as its congener in destroying 
hairy caterpillars, and appears to be almost equally destruc- 
tive to the gypsy moth larvae. From personal observation, 
as well as from reports of the observations of others, I am 
led to believe that this bird does not feed as rapidly as the 
yellow-billed cuckoo, and spends more time in beating the 
caterpillars, perhaps for the purpose of killing them, or pos- 
sibly to divest them of their hairs before eating them. In 
the end, however, the caterpillar is swallowed whole. Like 
the yellow-billed cuckoo, this species feeds the caterpillars 
to its young. 



MOST USEFUL BIRDS. 213 

Neither species of the cuckoo is very numerous in the 
infested region, but both are fairly common and both are 
attracted by the gypsy moth to badly infested orchards or to 
the edges of badly infested woodland. Five cuckoos have 
been seen at a time in an infested tree. In some infested 
places they may be found at times in considerable numbers, 
and the number of larvae they destroy is astonishing. They 
frequently take larvae from under the burlaps. 

Baltimore Oriole. — The oriole, like the cuckoo, is a well- 
known destroyer of the tent caterpillar ( Glisiocampa Ameri- 
cana) and other hairy larvae. Several observers have seen 
this bird taking gypsy larvae from the burlaps. In 1894 in 
an orchard in Winchester four orioles were seen to follow 
along the rows of trees, flitting from burlap to burlap, and 
taking the larvae from under the cloth. The birds would 
hang to the burlap while turning up the edges and running 
their bills beneath. The young orioles frequently enjoy a 
gypsy moth diet, and the adult birds have been seen day 
after day feeding their young with these insects. 

Only three orioles' stomachs have been dissected. One 
contained four nearly full-grown gypsy moth larvae, another 
two, and one was empty. These dissections probably did 
not fairly indicate the value of these birds as caterpillar de- 
stroyers, as the orioles have been seen to kill caterpillars of 
which they ate only a small portion. 

Catbird. — Where the gypsy moth has penetrated into 
thickets, the catbird feeds on ^^ 
the larvae, and, as the season ^^L 
advances, destroys many of ^^_,^pJb 
the pupae, taking both these ^gaftj^ JH^^ 

tonus of the moth to its 5|3 Hr 

young. That this habit is ^j K§J_-_- 

<|iii[c constant is evident, as --^m SPSSl ■p|pP* i,ir ' 
the catbird was seen feeding ^sP— ^ 

on the larvae in 1891, and ~" ~''JJN& 

almost daily through a con- 
siderable portion of the sum- 
mer of 1895 hj observers in several different towns. The 
catbird has been seen to take larvae of all sizes to its young. 
It is one of the birds that frequent badly infested localities. 



Fig. 30. Catbird. 



214 



THE GYPSY MOTH. 




Fig. 31. Chickadee. 



Chickadee. — The chickadee, though a small bird, feeds 
quite constantly on the gypsy moth larvse, "skinning" or 

tearing to pieces the larger larvse 
which it cannot swallow. On cap- 
turing a large specimen the bird 
usually stands on the caterpillar, 
striking it with its bill until the 
skin is torn open, when it pro- 
ceeds to eat the vital parts. 
Sometimes the chickadee eats 
nearly all of a large larva. This 
bird is also fond of the pupse, 
usually breaking them open and 
eating a small portion of the 
body tissues and juices. Chick- 
adees have been seen to feed on 
the female moths. 
Blue Jay. — In infested woodlands or in orchards near its 
favorite haunts the blue jay is most useful as a caterpillar 
hunter. Mr. M. J. Flood, formerly in the employ of the 
Board, who was stationed in 1891 at a badly infested locality 
in Arlington, where he watched the gypsy moth larvse for 
forty-eight hours, reported that he saw hundreds of the 
larvse picked up by this bird. During the day he saw six- 
teen blue jays eating the larvse and pupae, which he could 
see very distinctly as the birds held them in their bills. 
These birds are known to be regular visitors to badly in- 
fested trees, yet they are so wary that it is difficult to observe 
them closely. The prying nature of the blue jay stands it 
in good stead in searching out hidden larvse. It pecks 
them from the crevices of the bark or from under the bark 
on dead limbs, and searches every hole. It frequently visits 
burlaps on infested trees, thrusting its bill under the burlap 
and raising it enough to draw out the hidden larvse beneath. 
Mr. Mosher reports having seen the blue jays feeding larvse 
and pupse to their young. The jays have been frequently 
seen carrying the larvse in their beaks, probably with the 
intention of feeding them to their young. Sometimes they 
pinch or hammer the larvse, killing them in wanton sport or 



MOST USEFUL BIRDS. 



215 



maiming them and dropping them upon the ground. This 
habit of killing and dropping larva? has been observed else- 
where.* 







Fig. 32. Blue jay. 

Chipping Sparrow. — Though the chipping sparrow does 
not rank high among insectivorous birds, and feeds largely 
upon seeds during certain seasons of the year, it nevertheless 
destroys very many in- _j W-^- 



sects, especially lepi- 
dopterous larva?, which 
are injurious to trees 
and garden plants. It 
is often seen chasing 
flying gypsy moths. It 
appears to be fond of 
gypsy moth caterpillars, 
and I have frequently 
observed it in badly 
infested spots catching 
and killing large larvae 




Fig. 33. 



Chipping sparrow. 

A young chipping sparrow shot 
and dissected contained a nearly full-grown larva of the 
gypsy moth, which had been swallowed head first. 

In 1891 Mr. E. P. Felt confined (for experimental pur- 



* Dr. C. M. Weed in the Ninth Annual Report of the Ohio Agricultural Experi- 
ment Station, 1890, p. lv. 



216 



THE GYPSY MOTH. 



poses) a number of gypsy moth caterpillars in nets on the 
branches of apple trees. It was found almost impossible to 
complete the experiments, as many of the caterpillars dis- 
appeared from the nets. An examination of the nets showed 
that they had been broken open in some unknown way. I 
watched one of the nets and saw a chipping sparrow break 
through the netting and secure one of the larger larvre. As 
these birds were frequently seen about the nets, it is probable 
that they were responsible for the abduction of many larvas 
which disappeared. Mr. Felt says in his notes that sixty 
per cent, of the larvas used in the experiments were taken 
by birds which broke into the nets. There were very few 
of these larvee in the vicinity, except those confined in the 
nets. 

Robin . — The robin has been reported by several observers 
as feeding upon the larva? of the gypsy moth, and by one as 
feeding upon the pupse. One observer believes the robin to 
be the most useful bird of all ; but the notes on this bird are 
lacking in detail. I can say nothing from personal observa- 
tion in regard to its habits of feeding on the gypsy moth, 
except that it has been often seen feeding on the ground 
about apple trees frequented by the gypsy moth, or upon the 
lower branches of such trees, also in trees in badly infested 
woodland. 

Red-eyed Vireo. — This bird has been seen by many observ- 
ers to feed on the gypsy moth larvse. It probably feeds its 
young quite regularly on the larvse. The vireos are known 

to be caterpillar hunters, but 



are believed to prefer smooth- 
skinned species. They, how- 
ever, frequently break open 
the nests of the tent cater- 
pillar to get at the hairy 
larvas within. This bird usu- 
ally places the gypsy moth 
larva on a limb, and pulling 
it to pieces eats the pieces 
separately ; yet it has been 
seen often to eat the larva 



¥ ; 




1 




Fig. 34. Red-eyed vireo. 



whole and also to feed it alive to the young birds. 



MOST USEFUL BIRDS. 217 

Yelloio-throated Vireo. — Mr. C. E. Wood, an inspector 
in the employ of the Board, writes that he saw a yellow- 
throated vireo take a large larva, alight on a limb with it, 
and, placing one foot on it, peck its head off and give the 
body to a young full-fledged bird which was waiting to be 
fed. The young bird took the body of the larva, placed it 
on the limb under one foot, and, pecking off a few small 
pieces swallowed the rest whole. The yellow-throated vireo 
has been seen by several observers to catch and eat the 
larva?, and is probably nearly as useful in this respect as 
the red-eyed vireo. 

Crow. — The crows in the infested region are so shy that 
it is difficult to get near enough to them to observe care- 
fully their feeding habits. It was not until 1895 that they 
were actually seen to feed upon the gypsy moth, though it 
had been noted that they sometimes frequented badly infested 
places. They had also been seen to take their young to in- 
fested localities, where they were apparently feeding them 
with the larva? or pupa?. In the summer of 1895 the prob- 
ability of their feeding upon the gypsy moth was made a 
certainty by the observations of Mr. Mosher, whose work 
in observing birds has been done with the most painstaking 
and patient care. 

The prying, inquisitive habits of the family are well illus- 
trated by the crow when searching for gypsy moth larvae and 
pupa?. Dead bark is torn off from branches, clumps of 
bushes are penetrated, and rubbish on the ground is over- 
hauled by the bird in its search for the insects. Mr. Mosher 
watched a crow which alighted within thirty feet of him on 
a branch above his head, and fed upon the gypsy larva? with- 
out noticing his presence. By using an opera glass all the 
motions of the crow in searching for and capturing its prey 
were readily seen. The crows will alight upon the branches 
and search the under sides, where the gypsy moth caterpil- 
lars crawl or cluster. They are apparently quite fond of the 
pupa?, and will also eat the female moths. The young crows 
kept at the insectary were fed almost exclusively for two or 
three days upon these insects. Although they ate them at 
first with avidity, they soon refused them and would not 
touch them so long as other food could be obtained ; neither 



218 THE GYPSY MOTH. 

would they capture and eat the larvae. When the first moths 
were placed in the cage, they caught and ate them eagerly. 
The larger crow ate eighty- three and the smaller thirty-three. 
On the second trial, crow number one ate fifty-eight moths 
and crow number two twenty-three, thus together destroying 
eighty-one. On the third trial they would have none of them. 
At first, the birds, being apparently quite hungry, devoured 
them whole. Later they rejected the thorax with the wings 
and other appendages, and took the soft abdomens only. 
The birds were at first so eager for the moths that they 
would snatch them from each other. A curious fact about 
their eating was that they swallowed the moths hind end 
first, while grasshoppers were always swallowed head first. 
It would appear from this limited experiment that the crows 
soon became tired of a gypsy moth diet. It is quite prob- 
able that unconfined crows would tire of the moth as food 
were no other food available. Yet from the frequency of 
the crow's visits to the infested spots, the size and capacity 
of the stomach, and the number of different forms of the 
moth eaten, it may be inferred that this species is quite use- 
ful in destroying the gypsy moth. 

Other Useful Birds. 

Bluebird. — In 1891 the bluebird was often seen feeding 
on the larvae and pupae of the gypsy moth, but this was not 
noticed in the ensuing years, and in 1895 no bluebirds were 
seen during the summer in the infested region. When blue- 
birds breed in or near an infested orchard, they will no doubt 
destroy many of these insects. 

Warblers. — Although certain warblers have been seen 
occasionally to capture many of the gypsy caterpillars and 
moths, it is difficult to determine by observation or dissection 
how useful they are in this respect. Owing to their activ- 
ity, and the small size of the larvae usually taken by them, 
it is often impossible to learn the species or the number of 
insects which they eat. The great vernal flights of warblers 
through the infested region occur in May, at a time when 
the larvae of the gypsy moth are very small, and are either 
feeding or resting upon or underneath the leaves. The birds 
migrating northward restlessly move from tree to tree, and 



OTHER USEFUL BIRDS. 219 

accurate observation of their feeding habits is then difficult. 
As warblers glean much of their food from the twigs and 
foliage, it is highly probable that the mortality among the 
small caterpillars is partly caused by these birds. 

Observations on the feeding of the warblers were made 
when the spring migrants had gone north and the sum- 
mer residents were breeding. The warblers which breed in 
the infested districts do not appear to feed habitually on the 
gypsy moth. Both observations and dissections indicate that 
most of them prefer the small, smooth, geometrid larvce. All 
of them appear to have a particular fondness for the canker- 
worms, and a few eat the tent caterpillar. Yet some of the ob- 
servations made show that certain species of warblers destroy 
many of the larger gypsy caterpillars. These species also 
destroy moths, both male and female. Mr. Bailey saw a yel- 
low warbler take two large gypsy moth larvse, tear them 
open and eat out the body contents, leaving the skins upon 
the tree. He saw a black-and-white creeping warbler just 
from the nest capture and eat seventeen gypsy moth cater- 
pillars. All of them were pecked open. 

Mr. I. C. Green, a former employee of the Board, consid- 
ers the redstart the most useful of all birds in destroying the 
gypsy moth, but does not give the details of his observations. 
This species has been seen by other observers to feed espe- 
cially on the male moth, which it often captures in flight. 

The oven bird is mentioned by several observers as feed- 
ing on larvte and moths. The other warblers in the list 
have seldom been seen to take any form of the moth. 

Sparrows. — Though the towhee bunting or chewink was 
not seen preying on the gypsy moth prior to 1895, the 
observations of Mr. Mosher give ample proof of its useful- 
ness in this respect, especially in woodland or in sprout- 
land where it is a common bird. It eats readily all forms of 
the moth excepting the eggs, and this habit has been fre- 
quently observed. The rose-breasted grosbeak and indigo 
bird occasionally eat the larvae. 

Flycatchers. — All the flycatchers which breed in the dis- 
trict are given in the list of birds which .destroy the moth. 
Though most of them kill a great many moths, they proba- 
bly are not as useful as most other birds on the list, as they 



220 THE GYPSY MOTH. 

pursue mainly the quick-flying male moths. Experience in 
trapping male moths has shown that ordinarily their capture 
has little effect on the number of fertile egg-clusters in a badly 
infested spot. This is partly because most of the male moths 
find their mates close at hand, and so fertilize females before 
taking any extended flight ; and partly because the male 
being polygamous, each one that escapes the birds may fer- 
tilize several females. Yet as very many of the males are 
caught by flycatchers, this may account for the scarcity of 
males and the number of infertile egg-clusters sometimes 
found in badly infested localities. As many males emerge 
before the females, and as the moth lives but a few days 

in the perfect form, most of 
the males usually die before the 
females all emerge, and males 
are comparatively scarce late 
in the season even in a badly 
infested locality. If at this 
time the flycatchers and their 
young frequent an infested lo- 
cality, they still further reduce 
the number of surviving male 
moths. This scarcity of male 
moths late in the season, which 
is in part caused by the flycatchers and other birds, may 
prevent the fertilization at that time of many eggs. Yet the 
good done in this way by the flycatchers may be counteracted 
by their destruction of hymenopterous parasites of the moth. 
Of these parasites the ichneumon flies appear to be the 
most useful, yet even they have not proved at all effectual 
in reducing the numbers of the gypsy moth, even under the 
most favorable circumstances. Mr. Kirkland has seen a wood 
pewee dart down and capture an ichneumon fly, apparently 
Theronia melanocephala. This fly sometimes attacks gypsy 
caterpillars, and has been frequently seen searching over 
trees infested by them. Occasionally a flycatcher will pick 
up a spinning larva as it hangs swaying in the wind by 
its thread from the tree, but there seems to be no reason to 
believe that this is a habit. Though the flycatchers confine 
their feeding on this insect mostly to the male moths, they 




OTHER USEFUL BIRDS. 221 

frequently take females, and doubtless destroy many in the 
aggregate during a season. The king bird appears to be the 
most useful flycatcher in this respect, and has been seen to 
eat very many of the females. This bird may thus render 
efficient service to the farmer by preventing the deposit of 
many thousands of fertilized eggs. Its comparative value 
as a gypsy moth destroyer depends largely upon the number 
of female moths that it kills. 

Woodpeckers. — Of these most useful birds the three resi- 
dent species have all been seen feeding upon the caterpillars 
or pupae of the moth. 

The flicker has also been seen carrying caterpillars to its 
young. Mr. W. C. Colt, an inspector in the employ of the 
Board, says that he watched a female flicker take nearly full- 
grown larva? to its young. The bird made regular trips to 
its nest at intervals of from three to five minutes. The 
downy woodpecker was observed by Mr. Bailey to eat a few 
caterpillars, and to peck many others and afterward drop 
them from the tree to the ground. 

From what is known of the habits of woodpeckers, it was 
expected that they would be found to feed on the gypsy 
moth pupae. The downy and hairy woodpeckers are known 
to feed in winter to a greater or less extent on the hibernat- 
ing pupae of many insects. Yet the hairy woodpecker only 
has been observed to peck into the pupae of the gypsy moth. 
This bird is not at all common in the district, but both 
old and young birds have been seen feeding upon the pupae 
by Mr. Mosher. 

There is much difference of opinion among observers as to 
the comparative usefulness of certain species of birds in 
destroying the gypsy moth. This is to be expected, as each 
is prone to regard his own observations as conclusive in 
respect to all the species which he observes. In drawing 
conclusions from observations on the food of birds a great 
deal must be allowed for their individual preferences and 
acquired tastes. For example : several observers report the 
red- eyed and yellow-throated vireos as feeding eagerly on 
gypsy moth caterpillars. Mr. Henry Shaw notes that in 
one infested locality the red-eyes appeared to be living on 
them, eating them constantly. Mr. C. E. Wood has seen 



222 THE GYPSY MOTH. 

the yellow-throat go from burlap to burlap, drawing out the 
larvae from beneath. Yet Mr. Bailey reports that he has 
seen individuals of these species search a tree over for hair- 
less larvae before they would eat one of the caterpillars of 
the gypsy moth, of which there were thousands on the tree. 
I do not question the correctness of any of these observa- 
tions. Certain fowls or flocks of fowls in the infested 
region ate the caterpillars with avidity, while other individ- 
uals or flocks would not touch them. The same individual 
preference was noticed among toads. 

It appears that the presence of a great number of hair- 
less larvae has the indirect effect of lessening the number of 
gypsy moth caterpillars destroyed by birds. When canker- 
worms are plentiful, the birds eat comparatively few of the 
hairy caterpillars until the canker-worms have disappeared. 
Although many gypsy moth caterpillars were eaten very 
early in the season of 1895 by the orioles, vireos and other 
birds, these caterpillars received very little attention later, 
when the growing canker-worms became more noticeable. 
Most of the birds then devoted their attention to the canker- 
worms. About June 10, when the canker-worms had mostly, 
disappeared, the birds again attacked the gypsy moth larvae 
and continued to feed upon them for some time. Their appe- 
tites for these insects appeared finally to wane, having been 
apparently cloyed by an excessive diet of hairy caterpillars. 
It has been noticed that sometimes birds tire of a monotonous 
diet, and that they will even cease to feed for a time upon a 
favorite insect prey. This may partially account for the fact 
mentioned by Grimm, that the birds forsook the Russian 
forest which had been devastated by the gypsy moth. Yet 
this would not be a sufficient reason to account for a continued 
absence, as birds often return to feast again after a change of 
diet. But the lack of shade, water and green food, all of 
which together make a region unfit for the habitation of wood 
birds, may have driven them for a time from the devastated 
forest. In the infested district in Massachusetts forest birds 
will not remain constantly through the hot summer days in 
woodland which has been stripped by the gypsy moth, but 
will betake themselves to shaded glades and brooksides, mak- 
ing frequent sallies into the bare, infested woods to feed on 
the pest. 



BIRDS FEEDING ON THE MOTH. 223 

Birds attracted to Infested Localities. 

The attraction of birds to infested localities and the num- 
bers of gypsy moths destroyed by them there may be best 
realized by visiting a badly infested spot at a season when 
all forms of the insect are to be found upon the trees. At 
such a time the birds which feed upon the moth may be 
observed to the best advantage. For this purpose one 
should rise before daybreak and be on the ground before 
sunrise, as many birds are in active pursuit of insects at that 
time. 

Upon approaching at dawn a badly infested spot in wood- 
land, the stroke of a flitting wing, the rustle of dead leaves, 
an occasional shower of scattering dewdrops, a chirp or alarm 
note heard here and there, all denote the presence of birds in 
the woods. Their forms are still hidden or only dimly visible 
in the uncertain, growing morning light. The infested spot 
has the appearance of an opening or clearing. We emerge 
in what appears to be a dead forest. The trees wear no foli- 
age. The pines, oaks, birches, poplars and wild cherries are 
stripped and bare. The few leaves which still hang upon the 
young maples and walnuts only accentuate the general naked- 
ness. There are sounds, not of the wind or storm, and yet 
akin to these, pervading the woods, — sounds as of dry 
leaves stirred by a rising breeze, mingled with those of the 
tine pattering raindrops of sudden showers. These are caused 
by the hosts of gypsy caterpillars which have devastated the 
woods. The sound of their feeding is in the air, their 
excreta rattle like raindrops on the dead leaves. As the 
rising sun throws level beams across the hillside, the tracery 
of the bare, interlacing branches and twigs is reproduced 
upon the barren upright rocks of a rugged ledge. There is 
little or no summer green, except the moss on the stones 
along the stream, and a few small shrubs which have not 
yet been wholly stripped. Upon the bare trees, especially 
those near the edges of the defoliated tract, hundreds of 
thousands of hairy caterpillars swarm. Many of them are 
now hurrying down the trunks and crawling away to places 
of concealment, seeking shelter from the sun's rays. Many 
more, having been travelling perhaps throughout the night 



224 THE GYPSY MOTH. 

in search of food, are still crawling in search of it, either on 
trees or upon the ground. Masses or swarms of caterpil- 
lars are clustered in every sheltered place ; thousands are 
feeding on the leaves of trees near the borders of the deso- 
lated area. The pupae hang in bunches under the limbs 
and in the crevices of the larger trees. Many female moths 
are just emerging from the chrysalides, and others are drying 
their wings. This is the appearance presented by a wood- 
land colony of the gypsy moth on a July morning. 

Seated here, somewhat screened by the remaining herbage 
on the borders of the stripped tract, we may observe the 
strusrsrle for existence between the moth and other forms 
of life. From the harsh semi-conversational notes beard, 
first solemn and wary, then growing animated and cheerful, 
we judge that a crow is feeding its fledged young in the 
vicinity. Soon the crows are seen flying near. They alight 
about forty yards away by the brook, and the old bird, go- 
ing to a clump of bushes, feeds her young time after time 
with something she takes from among the stems. With 
a glass we can see her take the larvae and pupae and put 
them into the open beaks of her eager young. The old bird 
now finds a female moth and passes it to one of the brood. 
Soon becoming alarmed by some movement on our part, they 
fly away to some pines, where in the high branches they 
resume their feeding. An examination of the bushes they 
have just left shows that the old crow has taken nearly all 
the larvae, pupae and moths from the clump, leaving only a 
few moult skins and spun threads to mark the recent ex- 
istence of the moth there. 

A family of chickadees now appear. Flitting about 
among the trees, they begin to catch and eat the larvae. One 
picks up a large caterpillar, places both feet upon it and eats 
out the viscera, leaving the head and skin. Another pecks 
a caterpillar into small pieces and apparently eats most of the 
pieces. Number one now flies some ten yards with a large 
larva which it has just seized. Alighting on a convenient 
limb, the bird hammers its prey awhile and finally drops it, 
mutilated and dying, to the ground. Another bird tears a 
female moth in pieces, eating only the contents of the abdo- 
men. All devote more or less time to killing the pupae, eat- 



BIRDS FEEDING ON THE MOTH. 225 

ino 1 only a small portion of each. Thus with cheery chirp 
and call they flit about through the woods, killing and eat- 
ing as they go. A red-eyed vireo alights on a branch within 
six feet of us, and, picking three half-grown larvae from the 
leaves, swallows them head first and flies away towards the 
brook. Something is scratching in the leaves a few yards 
away. With the glass we can see four towhees scratching 
and digging like chickens. They are searching for the pupae 
which they greedily eat. If a male moth flies low overhead, 
one of these birds will leap from the ground and capture it. 
They search about upon the ground and among the small 
shrubs and seize the newly emerged females, beating them 
on the ground and finally swallowing them. A lone cuckoo 
whose dismal notes we have just heard now comes down 
from a near-by tree, alights on a small sapling and proceeds 
to breakfast. It picks off fourteen caterpillars, one by one, 
hammers the larger ones a little and then swallows them 
whole. A family of brown thrushes is busy by the brook. 
With the glass one of them can be plainly seen in the act 
of taking pupae from the stem of one of the larger bushes. 
A family of five black-and-white creeping warblers come in 
sight. They run and climb about on the trunks and branches 
of the stripped trees, picking up the smaller larvae of the 
gypsy moth and other insects, and now and then darting into 
the air after flying male moths or pecking at the females. 
These females they rarely eat and sometimes do not mate- 
rially injure, though they knock many of them off the trees. 
One female which falls is snapped up by a towhee which 
springs from the ground to take it in the air. A single 
Baltimore oriole flies in, looks about as if out of its element, 
catches several larvae and disappears in the direction of the 
highway. The harsh cries of the blue jays have been ring- 
ing for some time through the woods. One at a time, five 
jays pass among the trees. With the glass we can see two 
of them taking the large larvae from a tree trunk. They 
fly with them to branches or to the ground, and eat them 
there. You can plainly see the jays as they take the cater- 
pillars in their bills, but they are so shy that they will not 
remain long within our range of vision. Now the chicka- 
dees are back again. One of them takes twelve pupae in 



226 THE GYPSY MOTH. 

succession, carries each one to a limb, pecks it open and 
drops it upon the ground. 

As the sun grows warmer the number of male moths in 
zigzag flight increases. It is now six o'clock, and the snap- 
ping of bills heard on all sides tells us that the flycatchers 
are in the woods. Seven king birds are hunting the male 
moths. They catch scores of them, and occasionally they 
pick off a female or capture a falling larva. One of these 
birds comes in over the tree tops and hangs suspended on 
hovering wings. Suddenly dropping toward the earth, it 
picks up a fluttering female moth, and, flying to a limb, with 
a single snap of the bill divests the insect of both wings and 
swallows it. The bird then looks to right and left, flies from 
its perch, catches a male moth in mid-air, returns to its perch, 
swallows the moth and calls cheerily to its mate. The other 
king birds are all busy in like manner. As they seem to have 
settled down to remain for some time, we will keep tally of 
such moths as we can actually see them take at close range. 
Several chipping sparrows now appear hopping about on the 
ground. Now and then one picks up a half-grown larva. 
They are pecking and eating the female moths. They also 
chase and capture a low-flying male moth. Two catbirds 
are searching the thicket along the brook. They are taking 
pupte from the ground and dead leaves and also from the 
leaves and twigs of the low bushes, but we can see this only 
occasionally, as most of the time the birds are hidden from 
view. The crows went when the king birds came, but the 
flycatchers are still hawking about. As the reflected heat 
of the summer sun is radiated from the earth, the newly 
emerged male moths gain life and vigor from its warmth, 
and fly in large numbers through the woods. Three least 
flycatchers, two phcebes and several wood pewees are in sight 
and pursue the moths most of the time. 

At half-past nine the king birds have disappeared. Our 
tally sheet shows that we have seen them take seventy-nine 
male and twenty-four female moths. Tbey were watched 
only a portion of the time, but were feeding quite constantly. 
It is safe to say that between 6.15 and 9.30 they have killed 
two hundred and fifty male moths. The number of females 
taken cannot be so readily estimated. 



BIRDS FEEDING ON THE MOTH. 227 

One chipping sparrow lias been seen to take five females ; 
six least flycatchers, thirty-one males and nine females ; two 
wood pewees, twenty-two males and seven females. These 
birds were most of the time at a considerable distance from 
the point of observation, and it was only now and then when 
they approached quite near that their actions could be dis- 
tinctly seen. The phcebe appears to have taken male moths 
only. The towhees took eighteen moths, male and female, 
while on the ground. They then went into the trees, and 
while there moved on and were lost to view. A male yellow 
warbler appeared and was seen to eat a larva and a female 
moth. The oriole came again, taking four larvae. Redstarts, 
creeping warblers and chickadees come and go, feeding on 
the moth, but it is impossible to follow them and also watch 
the other birds. It is now eleven o'clock. The birds have 
nearly all left the hot and barren land of the defoliated hill- 
side, and are resting or feeding quietly in the shade among 
the leaves, where they cannot be so readily watched. 

Let us now go to an infested orchard a mile away, where 
not all the trees have been stripped by the caterpillars. Here 
we find some species of birds represented that were seen in 
the morning in the woods, but the catbird, the towhee, the 
creepers, the redstart, the wood pewee and the crow are 
absent. Yet we find here the robin, bluebird, yellow- 
throated vireo, flicker and house wren, all of which feed 
more or less upon the moth. As the afternoon advances, 
seven black-billed and four yellow-billed cuckoos are seen 
feeding on the larvae and pupre. There are yellow warblers, 
chickadees, half a dozen orioles, several chipping sparrows 
and other birds in the orchard. The few infested orchard 
trees appear to be much better protected by birds than the 
woodland, and the moth has not made so much progress 
here. 

In the waning summer afternoon we return to the woods, 
where, as the shadows lengthen, the birds again are busy. 
The kiug birds and other flycatchers and the chickadees are 
especially diligent. The king birds are now eating many 
of the female moths. A solitary scarlet tanager hammers 
a female moth upon a branch, shearing off its wings and 
then eating its abdomen. In the advancing; shadows of the 



228 THE GYPSY MOTH. 

approaching night many sparrows are seen hopping along 
the ground, where they find their evening meal. Although 
the birds are quite silent and it is impossible to make out the 
species as they move among the shadows, the white female 
moths can be plainly seen as the birds pick them up in their 
bills. Some fifty birds are seen busily feeding on the moth 
as we walk through the stripped woodland once more before 
leaving for the night.* 

Birds which destroy the Various Forms of the Moth. 

The birds which have been found preying upon the gypsy 
moth may be classified as follows : — 

Birds feeding on the larvae — chickadee, downy wood- 
pecker, wood thrush, yellow-billed cuckoo, black-billed 
cuckoo, yellow warbler, rose-breasted grosbeak, scarlet tana- 
ger, black-and-white creeping warbler, red-eyed vireo, chip- 
ping sparrow, oriole, blue jay, yellow-throated vireo, crow, 
catbird, black-throated green warbler, redstart, wood pewee, 
robin, English sparrow, least flycatcher, wren, Maryland 
yellow-throat, chestnut-sided warbler, brown thrush, purple 
grackle, oven bird, white-eyed vireo, bluebird, flicker. 

Birds feeding on the pupae — yellow-billed cuckoo, black- 
billed cuckoo, chickadee, yellow-throated vireo, towhee, hairy 
woodpecker, scarlet tanager, crow, catbird, oriole, blue jay, 
phoebe, English sparrow, brown thrush, king bird, wood 
pewee, bluebird, yellow warbler. 

Birds feeding on the male moths — king bird, chickadee, 
oriole, redstart, yellow warbler, towhee, wood pewee, yellow- 
throated vireo, red-eyed vireo, great-crested flycatcher, black- 
and-white creeping warbler, least flycatcher, phoebe, brown 
thrush, oven bird, English sparrow, chipping sparrow, blue- 
bird, indigo bird. 

Birds feeding on the female moths — king bird, chicka- 
dee, towhee, great-crested flycatcher, phoebe, black-and-white 
creeping warbler, red-eyed vireo, crow. 

Birds which possibly eat the eggs — downy woodpecker, 
chickadee, white-breasted nuthatch, blue jay, English spar- 
row. 

* This description of the feeding of birds upon the gypsy moth is taken from 
notes made in the field. 



BIRDS FEEDING ON THE MOTH. 229 



Do Birds feed on the Eggs of the Moth? 

The field agents employed in the gypsy moth work have 
often noticed egg-clusters of the moth which appeared to 
have been pecked open by birds. A large number of egg- 
clusters in the woods presented this appearance. Occasion- 
ally a bird was seen apparently pecking or eating the eggs. 
A single species which would feed on the eggs during all the 
winter months would be far more useful than many feeding 
on the caterpillars during the summer. The eggs are so 
minute that a bird feeding on them would destroy in one day 
more individuals of the species than another could in one 
hundred days by feeding on the large caterpillars. It could 
find these eggs for nine months of the year, whereas the cat- 
erpillars are to be found for less than five months. The de- 
struction of the eggs also prevents all injury to vegetation 
by the caterpillars, while if the eggs are allowed to hatch, 
the caterpillars may do considerable damage before they are 
killed. 

Wishing to do all possible toward protecting and fostering 
egg-eating birds, I determined to learn by accurate observa- 
tion and dissection whether any of our native birds were 
destroying any considerable number of the eggs. For this 
purpose Mr. Bailey was requested to watch birds during a 
part of the winter of 1894-95. He selected several stations 
for observation, one in an orchard and others in the woods of 
the Middlesex Fells. The stations in the woods were chosen 
because of the abundance of the egg-clusters of the gypsy 
moth in the vicinity of each. The station in the orchard 
was surrounded by a high board fence, built to prevent in- 
terference from without, and several hundred egg-clusters of 
the gypsy moth were exposed on a single tree. At all these 
stations bait was hung upon the trees for the purpose of 
attracting birds. Pieces of beef bone, suet, waste meat and 
grain were used to attract the different species. Crows, jays, 
nuthatches, titmice, kinglets, woodpeckers and tree creepers 
soon found the bait and made frequent visits to the infested 
trees. 

The birds soon became so accustomed to the presence of 
the observer that they would feed within a few feet of him. 



230 THE GYPSY MOTH. 

The chickadees became so tame that they would sometimes 
alight upon his hat or coat sleeve. They would come like a 
flock of chickens to be fed, and some would feed on limbs 
within three feet of his face. Occasionally one would even 
take food from his hand. In a short time chickadees, nut- 
hatches, creepers and downy woodpeckers became so tame 
that their feeding habits could be closely watched. Then 
observations were begun. A downy woodpecker was seen 
to strike an egg-cluster, scattering the eggs over the snow ; 
yet the bird did not eat any of them. On close examination 
it was seen that the eggs as well as some of the bark on 
which they rested had been removed by the bird to get at 
the larva of some insect which happened to lie under this 
bark. The birds which came to the bait on the infested trees 
Avere there many times each day for about three months, yet 
the eggs were seldom molested. During all this time, how- 
ever, the birds were feeding daily on eggs and other hibernat- 
ing forms of other injurious insects, of which they destroyed 
large numbers. Thirty-eight visits were made in one after- 
noon by birds to one tree on which were sixty-five gypsy 
egg-clusters. The birds all came within three or four feet 
of these eggs ; two of them even perched on egg-clusters, 
but they did not eat or even notice the eggs. Whether the 
result would have been the same had there been no meat for 
them to feed on, we cannot say ; yet, as they were constantly 
destroying the eggs of other insects, and as they occasionally 
pecked the egg-clusters of the gypsy moth but did not eat 
the eggs, it is fair to assume that they will not do so unless 
perhaps when driven to it by extreme hunger. As from 
observations made on birds in confinement it seemed prob- 
able that the hairs with which the egg-clusters are covered 
were disagreeable to the birds, an experiment was made to 
see if they would eat the eggs when the hair was removed. 
For this purpose some hundreds of eggs denuded of hair 
were glued upon a twig or stick in close proximity to the 
meat. The birds attacked the bait as usual, but if they 
ate any of the eggs it was not observed, although a few 
were knocked or pecked off. They would not eat the eggs 
even when they were cleaned of hair and distributed over 
the meat. No birds were actually seen to eat any of the 



BIRDS FEEDING ON THE MOTH. 231 

eggs. One hundred and ninety-one egg-clusters were put 
upon a tree to which from ten to thirty chickadees came 
daily. Only seventeen of these clusters were pecked open. 
In each case the bird was seen in the act. The eggs were 
pecked off or taken in the beak and dropped to the ground. 
A few blows would generally suffice to knock off most of 
the eggs. Ten birds which were pecking at the eggs were 
shot, but in no case were either the eggs or any portions of 
them found in the stomach or intestines. 

The observations showed that the egg-clusters were some ■ 
times pecked off by nuthatches, either in a search for hiber- 
nating larvte or pupse hidden beneath the clusters, or to 
secure the larvse of predaceous insects which bore into the 
egg-clusters and feed upon the eggs. No bird has actually 
been proved to feed upon the eggs except the English spar- 
row. One of these birds which was kept in confinement ate 
a few of these eggs from time to time when deprived of 
other food, but did not appear to relish them. It appears 
that very little can be expected from our native birds in this 
respect, unless they acquire a taste for the eggs. Yet many 
egg-clusters have been found which appear to have been 
pecked open or eaten by birds. The cause of this appear- 
ance was sought, and it was seen that squirrels and wood- 
peckers when climbing about on the trunks and branches 
of trees frequently tore off the eggs in running or climbing 
over the in, so that they presented much the same appearance 
as those actually pecked into by birds. The gray and red 
squirrels were seen in the act, as well as several species of 
birds. Chickadees have frequently been seen by men em- 
ployed in the woods to peck these egg-clusters, and several 
observations seemed to indicate that birds were feeding on 
them. The woodpeckers occasionally knocked them off the 
trees. Considering the prying, thieving nature of the jays, 
it is quite probable that they may peck into the egg-clusters 
and eat the eggs. Though the eggs are so tough that the 
smaller titmice might have difficulty in breaking their shells, 
the more powerful beak of the jay would easily accomplish 
this. 

In Europe, woodpeckers, creepers and titmice are said to 
perform great service by eating the eggs of the gypsy moth. 



232 THE GYPSY MOTH. 

Altum says that in the year 1848 endless numbers of the 
larvae of the gypsy moth had eaten every leaf from the trees 
of Count Wodzicki. In the fall all the trunks and branches 
were covered with the egg-clusters. Having recognized the 
uselessness of the attempt to remove them by hand, he finally 
o-ave up all his endeavors, and prepared to see his beautiful 
trees die. Toward winter numerous flocks of titmice and 
wrens came daily to the trees. The egg-clusters disap- 
peared. In the spring twenty pairs of titmice nested in the 
place, and the caterpillar plague was noticeably reduced. In 
the year 1850 the birds had so cleared his trees that he saw 
them during the entire summer in their most beautiful 
verdure.* 

Reaumur says that the larvse of the gypsy moth were very 
numerous in 1826 on the lines of the Allee Verteat Brussels. 
Many of the trees were stripped, and if one-half the eggs 
which were deposited that year had hatched, scarcely a leaf 
would have been left the next season, either there or in the 
park, where the eggs were numerous also ; yet two months 
afterward hardly one was to be seen. This destruction of 
the eggs he attributes to titmice, tree creepers and other 
small birds. f 

The Introduction of European Birds. 
If it is true that these European birds are so very useful 
in this respect, the comparative immunity of many European 
regions from the attacks of the gypsy moth may be due in a 
measure to their efforts. If such be the case, their introduc- 
tion into Massachusetts may well be thoughtfully considered. 
If introduced into a new country these feathered egg hunters 
might thrive and multiply exceedingly, and if the eggs of 
the gypsy moth are to them a familiar food, they would 
probably seek these eggs here in preference to the unfamiliar 
insect eggs which they would find. Such birds might in this 
way prove as useful as a small army of men. Yet what com- 
pensation would they exact for this service ? 



* " Forstzoologie," Vol. II., page 324, 1880. 

f "An Introduction to Entomology," by Kirby and Spence, Philadelphia, 1846, 
page 152. 



INTRODUCTION OF FOREIGN BIRDS. 233 

When the introduction of any bird or other animal from a 
foreign country is proposed, great care should be exercised to 
study thoroughly all phases of the subject. Often, when 
such importations have been made without careful scientific 
investigation, they have proved very expensive mistakes. 
The importation of the rabbit into Australia, the mongoose 
into Jamaica, and the sparrow into America and Australia, 
are familiar examples. The English sparrow was introduced 
here for the express purpose of suppressing such native 
pests as the larvse of the canker-worm moths. If previous 
to its introduction its habits had been carefully studied in 
Europe by a competent man appointed for the purpose by the 
United States government, its introduction might have been 
prevented. This exotic species, the value of which is doubted 
in its native home, was brought here to perform a task which 
native American species might have accomplished much bet- 
ter had they been protected and encouraged in our parks as 
the sparrow was. 

There are in Europe at least six different species of titmice. 
All of them are found in some of the countries where dispar 
is native. They are all recognized as eminently beneficial, 
and are regarded by foresters, entomologists and ornitholo- 
gists as among the most useful species in controlling noxious 
insects. Could they be successfully introduced here, they 
might do a vast amount of good not only in destroying the 
eggs of the gypsy moth but the larvae also, as well as the 
eggs of many other injurious insects. It is difficult to imag- 
ine that any harm could come from the introduction of these 
insectivorous birds, unless they should change their habits 
in some way or drive out our native species, especially the 
black-cap titmouse or chickadee, and fail to eat the females 
and eggs of the canker-worm moths which the chickadee 
devours in such quantities.* If that should happen, it 
would indeed be a catastrophe, as the chickadee is one of 
the most useful of all our native birds. 

No importation of birds should be blindly attempted. An 



* The great titmouse (Parus major) has been known to attack other birds 
and break open their skulls, eating their brains. Some species of European tit- 
mice are believed to do some injury to plantations of young trees by destroying 
buds or leaves. 



234 THE GYPSY MOTH. 

exhaustive study of their food habits should first be made 
in their native home, and all the possibilities of their intro- 
duction should be well considered. 

The English Sparrow and the Gypsy Moth. 

The English sparrow has been seen to feed on all forms 
of the gypsy moth ; yet this bird in its relations to dispar 
is injurious rather than beneficial to man. That its name 
appears so frequently in the records of observations is due to 
the fact that it has been for years the most common bird in 
villages and cities of the infested region, and that it is known 
to many observers who would be unable to identify most 
other birds. 

The sparrow was introduced into Boston Common in 1868. 
It is recorded that in 1871 it had reached Somerville, and 
in 1873 Lynn and Cambridge. It undoubtedly appeared in 
Medford about the same time, as Somerville adjoins both 
Medford and Cambridge, while Lynn is some ten miles east 
of Boston.* 

While it is no doubt true that native birds were a great 
factor in holding the moth in check during the first eight or 
ten years of its existence in this country when its numbers 
were few, it is equally true that the rapid distribution and 
increasing numbers of the English sparrow later from 1875 
to 1885 in the region infested resulted in driving out many 
native birds. The bluebirds, wrens, house swallows and 
martins were the first to leave, for as the sparrows multiplied 
they took by force the bird houses and cavities formerly occu- 
pied by these birds, compelling them to seek nesting-places 
elsewhere. As the sparrows further multiplied, their quarrel- 
some disposition impelled them to attack and drive away other 
birds found around their nesting-places. What they could 
not do singly they accomplished by force of numbers, until 
comparatively few native birds were able to breed in the 
immediate vicinity of the towns and villages. It is undoubt- 
edly true that the sparrow did something toward compensat- 



* See " The English sparrow in America," United States Department of Agricult- 
ure, 1889, page 21. I am informed by Mr. Walter Wright of Medford that his 
father, Elizur Wright, liberated several pairs of sparrows in Medford about that 
time. 



THE ENGLISH SPAEEOW. 235 

ins for this exile of insect-eating birds by destroying some 
of the smaller gypsy caterpillars and occasionally killing 
some moths or even eating a few moth eggs ; but it was 
noticeable that wherever the sparrow was most plentiful in 
the infested region, there also the gypsy moth became most 
numerous. This was due partly to a distribution of both 
species along the same highways and partly to the indirect pro- 
tection extended by the sparrow to the moth in driving away 
the latter's enemies among native birds. The caterpillars used 
the bird boxes occupied by the sparrows as a place of retreat, 
and the female moths deposited their eggs in these boxes. 
Sparrows and caterpillars formed a sort of happy family in 
the bird houses, which swarmed with both birds and insects. 
By driving the native birds away the sparrow became in a 
measure responsible for the phenomenal increase of the gypsy 
moth in numbers and its consequent destructiveness in Med- 
ford. The increase of some other injurious insects has been 
noticed wherever the sparrow has become so plentiful as to 
banish native birds.* The trees in Boston and some of the 
towns in its vicinity have often suffered injury from invasions 
of the Orgyia ieucostigma, or white-marked tussock moth, 
caused indirectly by this sparrow. The sparrow, having 
driven away the native birds, fails to make good their loss 
by destroying the hairy caterpillars. 

The ravages of leaf-feeding beetles (Chrysomela scalaris) 
have also become noticeable upon elm trees in localities most 
frequented by the sparrow. The imported elm-leaf beetle 
(Galeruca xanthomelcend) has also been most injurious in 
cities where the sparrow is abundant. 

The Distribution of the Moth by Birds. 

The dissemination of the moth in woodlands seems to indi- 
cate that it is distributed more or less by birds. This theory 
is substantiated by our observations. Isolated colonies of 
the moth are sometimes found in the vicinity of the nests 
of the larger land birds, such as crows, jays and robins. 
Occasionally birds flying to their nests with food for their 



* Second report on the " Injurious and other insects of the State of New York," 
by J. A. Linter, Albany, 1885, pages 80-82. 



236 THE GYPSY MOTH. 

young drop caterpillars or other insects. "VYe have a few 
instances on record where the gypsy moth caterpillars have 
been dropped in this way, and in one case at least the cater- 
pillar was not materially injured. 

Inspector Sanderson saw a wood thrush take a large cater- 
pillar from a tree and fly off with it. The caterpillar wrig- 
gled in the bird's hill and finally fell when the bird had flown 
a few yards. The bird did not come hack for it. 

On July 6, 1895, Mr. Bailey saw a blue jay flying over the 
woods in Saugus. It was flying about thirty yards from the 
earth, and appeared to be making quite a long flight. As it 
came near him he observed that it was carrying something 
in its beak, and he immediately shot at it with his revolver, 
not with the intention of killing the bird, but to make it 
drop what it was carrying. It dropped a large gypsy moth 
caterpillar, very nearly full grown. Mr. Bailey picked up 
the caterpillar, which appeared to be uninjured. He had 
watched the bird's flight for some distance, and thought it 
came about half a mile. The bird continued its flight north- 
ward, carrying the remainder of the food in its bill. Mr. 
Bailey kept and fed the larva, which pupated on July 12. 
A female moth emerged from the pupa on July 29, appar- 
ently in tine health. 

It is not an uncommon occurrence for birds when suddenly 
frightened to drop food, and when carrying several larvae 
in the beak at once, the oue nearest the end of the beak 
would be the one most likely to be dropped and also the one 
least liable to injury by the beak. Birds sometimes carry in- 
sects a short distance without any apparent purpose. Mr. 
Bailey saw a chickadee take seven larva? from a tree and fly 
away with them, dropping them ten feet or more from the 
tree. Three of these larvae were not injured. He also saw 
a least flycatcher carry away three female moths, only one of 
which it ate. One was dropped at a distance of twenty-live 
yards from the tree from which it was taken. 

There is- another way in which the caterpillars may be dis- 
tributed by birds. They are often hatched in holes of trees 
and in bird houses frequented by birds, especially by the 
English sparrow. When flrst hatched in such places, they 
are likely to spin down on their threads, and bird houses 



BIRDS DISTRIBUTING THE MOTH. 237 

and hollow trees have been found in which these spinning 
caterpillars were very numerous. The caterpillars may be- 
come attached to the feathers of birds which pass to and fro, 
and in this way may be carried short distances. Yet the 
danger of distribution by the accidental dropping of eater- 
pillars by birds in flight does not appear to be so great as 
that resulting from the dropping of caterpillars at the nest. 
It occasionally happens that hairy caterpillars wriggle out of 
the mouths of the young birds and are dropped into or below 
the nests. 

Mr. Bailey saw an oriole take to its young a caterpillar so 
large that the latter could not eat it. The young bird placed 
its foot upon the caterpillar, and drawing backward ejected 
and dropped it upon the ground. The old birds occasionally 
dropped food at the nest. Mr. Bailey watched a pair of 
chickadees bringing food to their young. They appeared to 
fly about half a mile to an orchard infested with the canker- 
worm, returning to the nest about once in twelve minutes 
with food. These birds dropped a few of the canker-worms 
just outside the nest. A new colony of moths was discov- 
ered in Cambridge not far from a badly infested locality. 
The appearance of the colony indicated that it was started 
by crows, as the larva? were scattered all about in the vicinity 
of the crows' nest. If several caterpillars of the same species 
are dropped in this way, there is a strong probability of a 
colony being formed in the vicinity of the nest. A bird may 
overlook a few caterpillars near its nest, preferring to go 
where caterpillars are plentiful rather than to search for them 
where they are scarce. It is probable, then, that the bird 
which is most useful in destroying caterpillars and which 
feeds the largest number to its young will be the most likely 
to aid in the distribution of the moth. The danger of dis- 
tribution would probably be greater in the case of the larger 
species of birds, were it not that a caterpillar seized in the 
bill of a crow would be more likely to be seriously injured 
than one taken in the bill of a small bird. The danger of 
distribution to distances of much more than half a mile by 
birds in this way does not seem to be great. 

Mr. Bailey watched a catbird taking food to her young. 
She flew back and forth about four times an hour. He 



238 THE GYPSY MOTH. 

could see her go and come for at least a thousand yards. 
She flew about twenty-five yards from the earth, going 
straight from the locality in which her nest was situated to 
the locality from which she procured the food. Other small 
birds have been known to fly an equal distance to secure 
food for their young. 

The distribution of caterpillars by birds goes to prove the 
rule that nature does not usually work for the extermination 
of species. While the birds are very useful as assistants in 
the work of extermination by destroying the gypsy moths, 
they hinder the work to some extent by distributing the 
larvse and the female moths. 

No appreciable distribution of caterpillars by birds will 
occur, however, except when caterpillars are present in large 
numbers, for then only will birds go to a distance to secure 
caterpillars as food for their young. Probably no other 
form of dissemination of caterpillars by birds will materially 
extend the moth's distribution even under the most favorable 
conditions. Wherever the caterpillars are present in large 
numbers in a settled country, they will be carried much far- 
ther and scattered abroad more widely by man and domestic 
animals than by birds. In woodlands remote from civiliza- 
tion, birds might be the principal factor in diffusing the 
moth to a short distance from badly infested spots, but the 
distribution of the moth in such places is not of so much 
moment as in cultivated and settled regions. If the moth 
were allowed to increase and spread over the whole State, 
we may infer that all possible distribution by birds would 
be of little importance as compared with the good they 
would do in checking the increase of the moth. 

In towns where the moths are few and where most of them 
have been already destroyed, and especially in small isolated 
colonies, birds are very useful allies in the work of extermi- 
nation. In such localities they take the caterpillars only 
when they come in their way, and rarely carry them to their 
young unless the nests are quite near the infested spot. 
Undoubtedly in many such cases birds have contributed as 
much toward the extermination of the moth as have the men 
employed in the work of extermination. Where the cater- 
pillars are few, therefore, birds render efficient assistance in 



BIRDS DISTRIBUTING THE MOTH. 239 

the work of extermination. As this work progresses, birds 
become more and more useful as destroyers of the moth and 
less dangerous as disseminators of the insect. 

There appears to be little if any danger of the distribu- 
tion of fertile female gypsy moths by birds, for, though birds 
have frequently been seen to carry the female moths a few 
feet or yards, the observations of five years have not afforded 
an instance of their carriage to a greater distance. The per- 
fect moths are to be found only in midsummer and later, a 
time when all of the larger and most of the smaller birds 
have no young in the nest. 

It is not probable that the birds distribute the eggs of the 
moth to any appreciable extent, though they undoubtedly 
scatter them somewhat by pecking egg-clusters from the 
trees. As it was known that many of the scattered eggs 
hatch, when denuded of their hairy covering, it seemed im- 
portant to determine whether birds would break the egg 
shells in feeding on the eggs, and whether unbroken eggs 
would pass through the digestive tract of a bird without in- 
jury to the shell and hatch if left exposed under natural 
conditions. Birds might thus distribute the moth as widely 
as they are known to distribute certain plants by scattering 
undigested seeds. A confined sparrow was fed upon the 
eggs of the moth, and it was found that most of them were 
broken by the bird's bill, or in the process of digestion ; yet 
some were passed entire. A similar experiment was made 
with the crow. As the crows would not eat the eggs of the 
moth unless disguised in food more to their taste, these 
eggs were inserted in the bodies of grasshoppers and other 
large insects, and while thus covered were swallowed by the 
crows. A small proportion of these esrgs were passed with 
the shell unbroken, but the life of the eggs appears to have 
been destroyed, as they are now drying up. This indicates 
that there is no danger of a distribution of living eggs to a 
distance by egg-eating birds. 

Although, as has been shown, certain species of birds 
undoubtedly assist in the distribution of the moth by carry- 
ing the caterpillars about, birds do much to prevent distribu- 
tion not only by reducing the numbers of the caterpillars, 
but by capturing male moths in search of isolated females, 



240 THE GYPSY MOTH. 

thereby preventing the fertilization of scattered females and 
the establishment of new colonies of the moth. Under the 
most favorable circumstances in open country and with favor- 
ing wind and weather the male will occasionally find a female 
at a distance of half a mile. It is probable that in orchards 
or woodlands the scent of the female does not travel so far. 
In any case a male flying some distance to a female would 
wander about a good deal before finding its mate. In the 
mean time it must run the gauntlet of the flycatchers, spar- 
rows, warblers and all the birds which so frequently capture 
flying males. It is to these birds a shining mark, and, 
although its flight is swift and eccentric, they readily follow 
and easily capture it. When flying low in the open land 
male moths are often pursued and captured by sparrows, 
They may also be captured by swallows, but this has never 
been observed. Experiments made in trapping male moths 
by attracting them to females have often failed because of 
the number of these moths captured Irr birds. Birds will 
sometimes capture every male moth before it reaches the 
trap. Therefore certain species do much in this way to 
compensate for the injury which they or others may do in 
distributing the moth. 

Birds versus Useful Insects. 
In their destruction of gypsy moths birds sometimes 
destroy parasites of these insects. The parasites within the 
caterpillars and pupae are eaten together with their hosts. 
Yet the immediate destruction of caterpillars by birds is 
of more importance to man than the lingering death which 
is caused by the parasite. The larvae of hymenopterous 
parasites feed almost exclusively on the fatty portions of the 
insects which they attack, thus allowing them to live, feed 
and grow, and do as much damage to vegetation as if they 
were not parasitized. When the caterpillar has finished 
feeding, or later when it has pupated, the parasite, having 
eaten the greater portion of the fatty substance, eats out 
the vitals, thus killing its host. The bird, on the contrary, 
snaps up the caterpillar at once, thus preventing further 
injury to the tree. The question then arises, would the 
parasite unhindered be more effectual in checking the rav- 



BIRDS VERSUS INSECTS. 241 

ages of its host than the bird ? It is possible that, should 
predaceous birds, insects and other enemies be insufficient 
in holding the moth in check, the conditions in the course 
of years, after great damage had been done, would be so 
favorable for the multiplication of insect parasites that they 
might check for a time the ravages of the moth. Experience 
in many countries shows that, where other enemies of a 
pest fail to hold it in check, insect parasites, starvation and 
epidemic diseases sometimes put an end for the time being 
to the plague. In addition to the destruction of parasites, 
together with the host, some ichneumons and tachinid 
flies are captured in the imago form by the flycatchers. 
Birds also destroy some of the predaceous insects. This 
is especially true of robins, jays and crows. Yet Pro- 
fessor Forbes has shown that the destruction of such insects 
by birds is not necessarily an evil.* The bugs which appear 
to be most useful in the destruction of the moth are believed 
to have some immunity from the attacks of birds by reason 
of their pungent secretions. Crows, however, destroy cer- 
tain of these bugs. 

Conclusions. 

Our present knowledge of birds as enemies of the gypsy 
moth in Massachusetts points to the following conclusions : — 

At least a dozen species are very useful in this respect ; 
probably twenty-five others are more or less useful, when 
the moths become very numerous, or when other species of 
insects which these birds prefer are scarce. 

Birds destroy larger numbers of the gypsy caterpillars 
when the canker-worms or other hairless larvse are scarce 
than when they are plentiful. 

Although birds gather in localities infested by the moth 
for the purpose of feeding on the caterpillars, they do not 
flock to such infested localities in such numbers as they do 
to regions infested by migrating locusts or by hairless cater- 
pillars. 

Birds are particularly useful in preventing the increase of 
small colonies of the moth, and in this respect are allies to 



* Bulletin No. 3, Illinois State Laboratory Natural History, November, 1880, 
page 83. 



242 THE GYPSY MOTH. 

man in the work of extermination. A few cases are noted 
in which such colonies appear to have been exterminated by 
birds. They are also useful in checking the increase of the 
moth in large colonies. 

More species of birds are found attacking the moth in 
orchards than in woodlands, though woodland birds often 
visit orchards situated near their usual haunts, and orchard 
birds visit badly infested colonies in woodlands. 

While birds are very useful in restraining local ravages of 
the moth, it is probable that should the moth be allowed to 
spread over the whole State, its increase would so outrun the 
numbers of birds that they would have no appreciable effect 
in checking its most serious outbreaks. 

The injury done by birds in distributing the moth and 
destroying parasites and other useful insects appears to be 
of' little importance when compared with the good they do 
in destroying the moth. 

If laws for the protection of birds were enforced, and if 
birds were fostered, encouraged and protected generally by 
citizens, there is no doubt that their efficiency as insect de- 
stroyers could be greatly increased. The most important 
service that could be rendered by birds in the case of the 
gypsy moth would be the destruction of the eggs. This 
service, supplemented by that of destroying the other forms 
of the moth in summer, would be of very material benefit. 
As no American birds appear to eat the eggs to any extent, 
it would be well to investigate thoroughly the habits of 
European egg-eating species, with a view to their introduc- 
tion into Massachusetts, if this should be found desirable. 

The Protection of Birds. 
It is quite evident that by pursuing a policy for the pro- 
tection of birds, the number of birds in the region infested 
by the gypsy moth and their efficiency as insect police could 
be greatly increased. While the present laws for the pro- 
tection of insectivorous birds are wise in the main, no 
adequate provision is made for their enforcement, and they 
are consequently a dead letter to certain classes of people. 
A great many birds are killed and many nests broken up 
by boys. In the fall the country swarms with gunners. 



PROTECTION OF BIRDS. 243 

Thousands of birds are killed for the milliners. The camps 
of Italians, where employees engaged in public works are 
quartered, furnish many of these gunners. These men will 
shoot birds of any kind, anywhere and on any man's premises. 
Everything that wears feathers is considered by them as fair 
game. 

The appointment of officers to enforce the bird laws might 
assist much in bird protection. Children in the public schools 
should be taught the usefulness of birds, and it should be 
generally considered a crime to destroy insect-eating birds. 
The farmer might as well allow men to steal his fruit and 
grain as to shoot the insect-eating birds on his premises. 
The number of birds destroyed by cats is astonishing. I 
have known a single cat to break up the nests of six pairs of 
birds in a day, destroying all the young and one of the old 
birds. Many wild and vagabond cats roam the woods and 
orchards and destroy thousands of birds. Outside the cities 
cats probably do enough injury by killing birds to much 
more than counterbalance all the benefit derived from them 
in the way of destroying rats and mice. A few traps prop- 
erly attended by a bright boy will do more towards clearing 
a place of rats and mice than half a dozen average cats. 

The number of such birds as nest in boxes or hollow trees 
can be increased by putting up boxes in which they may 
breed, and protecting them as far as possible from the English 
sparrow and other enemies. If evergreen hedges and patches 
of shrubbery are provided as retreats for birds to which they 
can ily when pursued by hawks, and if plenty of wild and 
cultivated fruit is grown in the vicinity, such a locality will 
be much frequented by birds. 

Birds may be attracted to infested localities in the winter 
or summer by supplying them with food and safe nesting- 
places. A people who protect and foster insectivorous birds 
cannot fail to add materially to the prosperity of agriculture. 



244 THE GYPSY MOTH. 



The Progress of Extermination. 

The extermination of the gypsy moth was begun by the 
Commonwealth under a misapprehension of the facts. When 
the first great outbreak of the pest was brought to the atten- 
tion of the Legislature in 1890, it was believed that the moth 
was confined to cultivated lands in the town of Medford. 
This infested district was not supposed to exceed one-half 
mile in width and one and one-half miles in length. The 
difficulty and expense of extermination were consequently 
underestimated. An appropriation was made for the pur- 
pose of exterminating the moth in this small tract and 
preventing its spread to other parts of the State. In the 
attempt to exterminate the moth, the experience of the first 
year showed that the insect was not confined to Medford, and 
the commission of 1890 reported that fifty square miles were 
more or less infested. The experience of the second year 
proved that the moth was distributed over an area of over 
two hundred square miles, not only in cultivated lands but 
in waste and wood lands as well. The magnitude of the task 
undertaken by the Commonwealth then became apparent. 

Circumstances favoring Extermination. 

There are certain circumstances connected with the habitat 
of the moth, which, taken together with known facts in its 
life history, encourage the attempt to secure its extermina- 
tion. 

Limited Area Occupied. — The experience of five years 
confirms the belief that the moth is confined to a limited area 
on and near the coast line. 

Favorable Location. — The infested region is bounded on 
the east and south-east by the ocean, which prevents the 
spread of the moth in those directions. Much of the territory 
along the coast consists of salt marsh, in which the gypsy 
moth cannot live. 

The infested region is in the most populous portion of 



EXTERMINATION. 245 

the State ; therefore tj^e extermination of the moth directly 
interests a large number of people. This fact assures the 
intelligent co-operation of many individuals. 

The original centre of infestation in the district was situated 
on a short line of railroad ending in Boston, and thus the 
danger of distribution by rail was not great. 

The Infested Area has been reduced. — As a result of the 
work of extermination, the region now occupied by the gypsy 
moth is considerably less than that occupied by it five years 
ago, when the work was begun. 

Slow Spreading. — The female moth does not fly. On 
this fact rests the principal hope of preventing the spread of 
the insect, and finally securing its extermination. Could 
the female moth fly, as does the male, the species would 
probably have been distributed long since over all eastern 
Massachusetts and adjacent parts of New England, if not 
farther. The moth occupied twenty years from the time of 
its introduction in spreading over the territory infested by 
it in 1891. 

The Moth hibernates in the Egg. — It remains in that 
form during most of the fall, the winter and early spring. 
The eggs are conspicuous, and an opportunity is thus given 
for inspecting the territory and discovering the colonies of 
the moth during the fall and winter months, while the trees 
are leafless and the insect is doing no damage. It is more 
feasible to exterminate an insect pest which may be attacked 
in the winter, when it is stationary for a fixed period, than 
to exterminate a species that can be reached only during 
the summer months, at which time its distribution is being 
effected. 

Obstacles to Extermination. 

Though there are many encouraging circumstances in 
connection with the problem, there are also serious obstacles 
to success. 

Enormous Reproductive Capacity of the Moth. — Its won- 
derful reproductive powers and its remarkable tenacity of 
life provide for a rapid increase and redistribution in an in- 
fested locality in the inspection of which a few moths may 
have been overlooked. 



246 THE GYPSY MOTH. 

Many Food Plants. — Where the moth is abundant, it is 
found on nearly all plants of economic value. In inspecting 
a region in search of the moth it is necessary to examine all 
species of trees. It is therefore much more difficult and 
expensive to locate all the colonies than it would be were 
the insects confined to a few food plants. 

Other Obstacles. — The infested region being densely pop- 
ulated, the danger of local distribution and reinfestation by 
man and animals constantly passing and repassing infested 
centres is much greater than it would be were the district 
thinly populated. 

No one method can be depended upon for exterminating 
the moth. Nature often defeats an attempt to exterminate 
by a single process at a particular season of the year. 
The most approved methods applied singly frequently fail. 
Exterminative work must proceed day after day throughout 
the year, to insure success. Though every effort was made 
in 1891 to exterminate the moth from the region most in- 
fested, the inspection of 1892 gave abundant evidence of the 
impossibility of extermination in one year's time. In 1891 
the destruction of the eggs was depended upon for extermi- 
nation. Yet caterpillars were found in 1892, even in those 
parts of the infested territory where the work had been most 
carefully done, and where the greater part of the eggs had 
been destroyed. Many of these came from eggs which had 
been scattered on the ground in the previous fall and winter 
before the work of destroying the clusters was begun. Eggs 
are sometimes thus scattered by the wind and rain, by 
people picking fruit or pruning or cutting trees, by birds 
and animals, or by various other causes. The female moth 
occasionally drops a few eggs upon the ground or in crevices 
of the bark, where they will escape the most thorough 
search. Spraying, as ordinarily done, will destroy only a 
small portion of the caterpillars. Bands of insect lime and 
other tree protectors merely prevent most of the caterpillars 
from ascending trees which have been first cleared of eggs. 
If thus kept out of trees, they will betake themselves to 
other plants. While the burlap bands afford a means of 
disposing of most of the caterpillars, there can be no cer- 
tainty of taking them all by this method. 




PLATE XXXVI. Men at work on the Dexter elm, Maiden. Prom a 

photograph. 



EXTERMINATION. 247 

The Success of Local Extermination. 
The work of extermination was begun on the principle 
that, if the moths could be exterminated from one tree, they 
could be eradicated from any number of trees, providing the 
same kind of work that cleared the first tree could be carried 
on simultaneously over a large area. It was soon found that 
the moth could be cleared from trees of ordinary size by 
honest, thorough, intelligent labor. Yet many doubters 
asserted that it was impossible to clear the larger trees. 
Medford, being one of the oldest towns in the State, had 
many very large elms. This was also true of Maiden. It 
was believed by some of the residents that it would be im- 
possible to clear the moths from these trees except by the 
aid of a balloon. The largest tree in the infested region was 
selected for trial of the possibility of extermination. This 
tree is situated on the property of the Messrs. Dexter of 
Maiden, and stands in front of the old Dexter mansion. 
The tree has been owned by this family for more than two 
hundred years. If not the largest tree in the State, it is 
one of the largest.* Early in 1891 an attempt was made 
to clear the moths from the tree, and a gang of four men, 
who had had some experience, went to work upon it to 
destroy the eggs of the moth. After working for several 
days upon the tree they reported it cleared. Another gang 
of men was put at work upon the tree, and six hundred 
additional egg-clusters were discovered. Notwithstanding 
this, caterpillars appeared in the spring upon the tree. It 
was then sprayed thoroughly, an extension ladder sixty-five 
feet in length being used, together with several additional 
ladders placed in various parts of the tree. Later in the 
season all the holes in the limbs were covered or filled, and 
the few egg-clusters found were treated with creosote oil. 
In 1892 the tree was banded with tarred paper, which was 
kept constantly moist with a mixture of tree ink, tar and 
oil. A few caterpillars were found, however, on the tree, 
having hatched probably from scattered eggs left in the 



* The Dexter elm has the following dimensions: circumference at base, 29 feet; 
circumference six feet from ground, 21 feet; height, 110 feet; spread from north- 
east to south-west, 104 feet. Some of the branches of the tree are 3 feet in 
diameter. 



248 THE GYPSY MOTH. 

crevices of the bark. In 1893 no caterpillars appeared, 
and no form of the moth has been found since 1892 upon the 
tree. In the inspections of the tree every care has been 
taken to go over it thoroughly, from its highest branches to 
the base of the trunk. The dead limbs have been removed 
and holes have been covered, but no other work has been 
necessary at the regular inspections. Plate XXXVI. shows 
men at work in the inspection of the tree. 

The extermination of the moth from many orchards was 
accomplished without much difficulty. Plate XXXVH. shows 
apple trees which were seriously injured during the season 
of 1891 by the gypsy moth. They were cleared of the moths 
and so treated that in 1892 they regained a large part of 
their foliage (Plate XXXVIH . ) . They have borne very little 
fruit, however, since 1891. 

Having learned that it was possible to clear the moth 
from any tree, it remained to be proved whether the creat- 
ure could be cleared from orchards or entire estates. 
Although in 1891 many estates appeared to have been 
cleared, there was still some doubt that the moths were 
exterminated from them. But the estates were examined 
again and again in succeeding years, and no moths were 
found except in a very few instances. The number of 
infested estates from which the moths had been cleared 
increased annually. Not only were estates cleared, but 
infested localities consisting of many estates were entirely 
freed from the moth. 

More than a thousand colonies in the infested region, some 
of them covering many estates, have been entirely cleared 
of the moth and have remained clear, until it has become an 
established fact that wherever the moths are found in open 
and cultivated lands, they can be exterminated. The diffi- 
culty of exterminating the moth in woodland has been found 
to be much greater. Yet, despite all obstacles, some of 
which at first seemed insurmountable, the moths have been 
cleared from certain infested localities in the woods. The 
destruction of all vegetation by fire will accomplish exter- 
mination in woodlands. But much of this infested woodland 
is retained by the Commonwealth for park purposes, and the 
destruction of the trees is out of the question, however much 




PLATE XXXVII. Apple trees stripped by caterpillars of the gypsy moth, 
Swampscott. From a photograph taken Aug. 5, 1891. 




: .*S*riK 




PLATE XXXVIII. View of the same trees in Swampscott a year later, 

after the moths had been cleared from the locality by the agents 

of the Board of Agriculture. From a photograph 

taken in July, 1892. 



EXTERMINATION. 249 

the exigencies of the case might seem to warrant such a course. 
Therefore burlapping, banding, spraying and other means, 
less expeditious and in the end more expensive than fire, 
have been resorted to. These means call for larger appro- 
priations than have yet been made, and without such appro- 
priations, promptly granted, the extermination of the moth 
can never be accomplished. Though a continual advance in 
the work of extermination has been made annually in the outer 
towns of the infested district, though some of them appear 
quite and others nearly cleared of the moth, there is a section 
of woodland in the inner towns which is probably in a worse 
condition than it was in in 1891. 

Larger Appropriations Needed. 
While the agents of the Board have been engaged in pre- 
venting the spreading of the moth and prosecuting the work 
of extermination in the outer towns of the infested region, 
they have been unable to do much more with the means pro- 
vided than to check the moth's annual increase in the central 
towns. This partial policy, the inevitable consequence of 
the inadequate appropriations, has necessitated in the inner 
towns an annual repetition of the work and expense with- 
out any considerable advance towards extermination in those 
towns. As a result, while extermination has been success- 
ful over large areas, principally in the outer towns, the 
moths have increased in the comparatively neglected wood- 
land in the central towns. The Board is required by law 
to do all possible toward preventing the spread and securing 
the extermination of the gypsy moth in this Commonwealth. 
All possible with the means at hand has been undertaken. 
All the evidence obtainable goes to show that the spread of 
the moth into territory outside the region infested in 1891 
has been prevented, and that extermination has been accom- 
plished both locally and over a considerable area, greatly 
reducing the infested territory. Our only hope of prevent- 
ing the spreading of the moth lies in doing everything possible 
to exterminate it. Therefore, whatever imperils the success 
of extermination, renders the prevention of the moth's dis- 
semination less certain. The expense of extermination has 
been greatly augmented and success retarded and gravely 



250 THE GYPSY MOTH. 

imperilled by inadequate resources and repeated delays in 
making the annual appropriations. Unless ample appropri- 
ations are promptly granted, failure is certain. 

To continue the past policy of inadequate and belated ap- 
propriations may result sooner or later in the escape of the 
moth from the territory to which it is at present confined and 
its final distribution over the whole country. In such a case 
it might injure the agricultural interests beyond calculation. 
If the gypsy moth should be allowed to spread over the 
United States, the average farmer would be powerless, under 
the conditions prevailing in this country, to protect his or- 
chard, woodland or garden against the ravages of this insect. 
Whatever afi'ects the prosperity of the farmer affects the 
prosperity of the whole people. Knowing as we do that the 
moth feeds on nearly all forest and orchard trees and garden 
plants, knowing also the injury done in Europe within the 
past century by this insect, having learned by experience the 
greatly increased destructiveness of European insects when 
introduced here, and considering the annual damage now done 
to agriculture by insects in this country (estimated by an em- 
inent authority at three hundred and eighty million dollars), 
we can but view with alarm the possibility of the spread of 
this insect over the United States. 

There is no doubt in the minds of those acquainted with 
the facts that the gypsy moth can be held in check where it 
now is and that it can be exterminated if sufficient resources 
can be secured and vigorous measures taken. It would seem, 
then, that the general government should seize the opportunity 
now presented to stamp out the pest which Massachusetts 
undertook to exterminate as soon as it was publicly known 
that it was within her borders, reducing its numbers and the 
area of its dissemination by local extermination and thus far 
holding it in check. The policy of control or extermination 
of insect pests by governmental commissions, which has been 
so successful in certain European countries, might be applied 
to advantage in this case by the government of the United 
States. There are those who believe that neither the State 
nor nation should appropriate money for the extermination 
of this insect, but that land owners should be left to protect 
their own property from its ravages. According to Professor 



EXTERMINATION. 251 

Fernald, this would prove to be the worst possible policy, 
as after the moths had spread over the State, the expense to 
land owners would be enormous as compared with the expense 
of the work as carried on by the State in the present re- 
stricted territory. He makes the following comparison in 
his report on the work of 1895, made to the gypsy moth 
committee of the State Board of Agriculture : — 

"The value of the taxable property in this State is 
$2,429,832,966, and an appropriation of $200,000 is a tax 
of less than one-twelfth of a mill on a dollar. A man having 
taxable property to the amount of $5,000 would have to pay 
a tax of only 41 cents and 6 mills. This beggarly sum of 
money would make but a small show in the work of clearing 
the gypsy moth caterpillars from an infested $5,000 farm* 
while in the uninfested parts of the State the land owners 
would be paying an exceedingly small premium to the State 
to insure them against the ravages of the gypsy moth. This 
premium on a $1,000 farm would be 81 cents, and for fifty 
years it would amount to only $4.16|. This protection 
would extend not only to farmers and owners of forest lands, 
but also to residents in villages and cities who own lands 
with trees and shrubs on them, and to vegetation wherever 
grown within the limits of our Commonwealth." 

The expense of this- work, if undertaken by the United 
States government, would be infinitesimal to the individual 
citizen and would be an economical insurance against the 
ravages of the moth on his property and that of his posterity. 



THE GYPSY MOTH. 

PORTHETEIA DI8PAR (L.). 



Part II. 



C. H. IF 1 IE IR, I£T _A_ Xj ID 










Insects mistaken for the Gypsy Moth. 



Explanation of Plate 39. 

Drawn in colors by Ella M. Palmer. 



It has seemed desirable to present colored figures of the following insects since 
in some of their forms they are the ones most commonly mistaken for the gypsy 



moth. 



1. Eggs of Euvanessa antiopa (Linn.) (Vanessa 

butterfly). 

2. Caterpillar of Euvanessa antiopa. 

3. Chrysalis " " " 

4. Imago " " " 

5- Egg-cluster of Clisiocampa americana Harr. 
(tent caterpillar). 

6. Caterpillar of Clisiocampa americana. 

7. Cocoon " » " 

8. Male imago of " " 

9. Female imago of " " 

10. Caterpillar of Orgyia antiqua (Linn.). 

11. Male imago " " " 

12. Egg-cluster of Orgyia definita Pack. 

13. Caterpillar " " « 

14. Male imago " " " 

T 5- Egg-cluster of Orgyia leucostigma (S. and A.) 
(the white marked tussock moth). 

16. Caterpillar of Orgyia leucostigma. 

17. Male imago of " " 

18. Female imago of " «* 



THE GYPSY MOTH. 



Porthetria dispar (L.~). 



This species was first described by Linnaeus, in 1758, in 
the tenth edition of his " Sy sterna Naturae," Vol. I, page 501, 
under the name of Phalcena (Bombyx) dispar, the specific 
name being given because of the marked difference or dis- 
parity between the sexes. In 1801, Schrank, in his "Fauna 
Boica," placed this species under his genus Laria; but this 
generic name had been previously used by Scopoli in the 
beetles, and thus, being preoccupied, could not properly be 
used for the moths. In 1810, Ochsenheimer, in the third 
volume of his " Schmetterlinge von Europa," established the 
genus Liparis and put dispar under it ; but Liparis is also 
preoccupied, and cannot be used. Hiibner, in his "Ver- 
zeichniss bekannter Schmetterlinge," page 160, published 
about 1822, placed dispar in his genus Porthetria with three 
exotic species, and therefore dispar, being the only European 
species, has been taken as the type. In the same work, page 
158, Hiibner established the genus Ocneria with rubea Fab. 
as the type, but Staudinger and some others, believing that 
rubea and dispar should be in the same genus, placed them 
with their allies under Ocneria. 

In 1829, Stephens, in his "Illustrations of British Ento- 
mology," Haustellata, Vol. II, page 55, established the genus 
Hypogymna and placed dispar under it. He also proposed 
this name in his catalogue the same year. In accordance 
with the laws of priority, almost universally accepted by 
zoologists, it is necessary to adopt the oldest tenable generic 
name which is not preoccupied ; and therefore Hlibner's genus 
Porthetria, with dispar as the type, was given by Kirby in 
his recent "Catalogue of Lepidoptera Heterocera," and has 
been adopted by Comstock and Dyar in this country. 



256 THE GYPSY MOTH. 

The question whether dispar shall remain under the genus 
Ocneria depends on whether it has the same generic charac- 
ters as rubea. If it has, then it should remain with rubea, 
otherwise it should be placed under the genus Porthetria. 
To settle this question to my own satisfaction, I sent to 
Europe and obtained specimens of Ocneria rubea, and, after 
a critical study of the structure, I am convinced that the two 
insects are not congeneric, and must be placed under differ- 
ent genera. On showing the insects to Prof. J. B. Smith, 
he agreed with me in my conclusions, and in a letter from 
Prof. A. R. Grote of Bremen, Germany, I learned that he 
had independently reached the same conclusion. I therefore 
feel obliged to adopt the name Porthetria dispar, given by 
Htibner over seventy years ago. In all our previous pub- 
lications, however, the name Ocneria dispar has been used, 
following Staudinger's catalogue. 

Common Names. 

The following are some of the common names which have 
been given to this insect in different European countries. We 
have adopted the common name "gypsy moth," because it is 
the one most frequently used in England, and has already 
come into very general use in this country. This name was 
first given to it, so far as I can learn, by Wilkes, in 1741 ; 
and Humphreys, in his "British Moths,*' says that "the 
popular name of the gypsy was no doubt suggested by the 
brown, tanned kind of color of the male." 

Schwammspinner : Fungus-spinner. The egg-cluster resembles a 

small tree fungus. 
DiGKKOPr : Thick -head. The head of the caterpillar is unusually 

large. 
Rosenspinner : Rose-spinner. They feed on rose bushes. 
Apricosenspinner : Apricot-spinner. 
Stammphal^ene : Stem-moth. The moths rest on the trunks of 

trees. 
Grosskopf : Great-head. 
Baumraupe : Tree-caterpillar. 
Schwammraupe : Fungus-caterpillar. 
Grosse Schwammraupe : Great fungus-caterpillar. 
Schwammmotte : Fungus-moth. 
Stammraupe : Stem-caterpillar. 
Grosskopfspinner : Great-head spinner. 



COMMON NAMES AND BIBLIOGRAPHY. 257 

Ungleicher Spinner : Dissimilar spinner. The sexes are very 

unlike. 
Ungleich Nachfalter : Dissimilar nocturnal-moth. 
Zweifach : Two-fold. 
Grosskopfbar : Great-head bear. 
Dickkopfiger Bar : Thick-headed bear. 
Le Bombyx dissemblable : The dissimilar bombyx. 
Le Bombyx disparate : The dissimilar bombyx. 
La Spongieuse : The spongy (moth). 
La Chenille commune : The common caterpillar. 
Le Zig-Zag. 
The Gypsy Moth. 
The Brown Arches. 

Literature on the Gypsy Moth. 
All the works in this list have been examined except those 
marked with an asterisk. 

Goedart, Histoire des Insectes, vol. I, pp. 118, 142, pi. 63, 16G2. 

Merian, Erucarum Ortus, etc., part I, pi. 18-31, 1679. 

Merian, Erucarum Ortus, etc., part II, pi. 19, 1683. 
*Blankaart, Schauplatz der Raupen, p. 25, pi. 6, figs. A-C, 1690. 

Frisch, Beschreib. von Ins., vol. I, p. 14, pi. 3, figs. 1-9, 1720. 

Frisch, Beschreib. von Ins., suppl., vol. XIII, p. 28, 1722. 

Merian, Erucarum Ortus, folio edition, pi. 183, 1730. 

La chenille a oreilles, Reaumur, Memoires, vol. I, p. 110, pi. 3, figs. 1, 
3-5; p. 19, pi. 4, figs. 1-4, 6-8; p. 352, pi. 22, figs. 5, 6, 8-10; p. 
359, pi. 24, figs. 1-4; p. 609, pi. 45, figs. 1-13; p. 614, pi. 46, figs. 1-7, 
1734. 

La chenille a oreilles, Reaumur, Memoires, vol. II, p. 63, pi. 1, figs. 11-15; 
p. 433, pi. 34, fig. 3, 1736. 
*The Gipsey Moth, Wilkes, Twelve New Designs of English Butterflies, 
1741-42. 

Roesel, Insecten Beliistlgung, part I, p. 17, pi. 3, flgs. 1-7, 1746. 

Schreber, Samml., vol. XIII, p. 153, 1750. 

Baumraupe, Schaeffer, J. C, Nachricht von einer Raupe, etc., 1752. 

Phalaena (Bombyx) dispar, Linn. Syst. Naturae, ed. 10, vol. I, p. 501, 
1758. 

SchaeSer, J. C., Der Wunderbare Eulenzwitter, etc., 1761. 
*Poda, Insecta Musei Graecensis, p. 86, 1761. 

Phalaena Dispar, ScopolU Ent. Carniolica, p. 197, 1763. 

Le Zigzag, Geoff., Hist. Abregee des Ins., vol. II, p. 112, No. 14, 1764. 
*Gronovius, Zoophylacium, vol. II, p. 208, 1764. 

Schaeffer, «T. C, Abh. von Ins., vol. II, p. 315, pi. 1, flgs. 1-8, 1764. 

Schaeffer, J. C, Icon. Ins. Ratisb., part I, vol. I, pi. 28, figs. 3-6, 1766. 

Phalaena (Bombyx) dispar, Linn. Syst. Nat., ed. 12, vol. I, p. 821, 1766. 
*Bombyx Dispar, Hufnagel, Berl. Mag., vol. II, p. 406, pi. 3, No. 16, 1766. 
*Bombyx Dispar, Hufnagel, Berl. Mag , vol. Ill, p. 8, No. 2, 1767. 

Merian, Hist. Generale des Ins. d'Eur , ed. 3, vol. II, p. 5, pi. 18, 1771. 

Bombyx dispar, Wilkes, English Moths and Butterflies, pi. 42, 1773. 



258 THE GYPSY MOTH. 

Phalaena dispar, Gleditsch, Forstwiss., vol. I, p. 310; voL II, pp. 45, 81, 

227, 739, 1775. 
The Gipsy, Harris, Aurelian's Pocket Companion, pp. 29, 30, 1775. 
Phalaena dispar, Christmann, Onomatologia Nat. Hist., vol. VI, p. 350, 

1775. 
Bombyx dispar, Fab., Syst. Ent., p. 570, No. 49, 1775. 
Phalaena dispar, Fuessl., Verz. Schweiz. Ins., p. 35, No. 660, 1775. 
Bombyx Dispar, Denis and Schiffermiiller, Syst. Verz. Schm., p. 52, No. 6, 

1776. 
Grosskopf, Mueller, O. F., Zool. Dan. Prod., p. 665, pi. 16, figs. 2-11, 1776. 
Phalaena dispar, Mader, Raupenkalender, p. 99, No. 282, 1777. 
Phalaena dispar, Fischer, J. B., Natur. gesch. von Livland, p. 151, 1778. 
Phalaena dispar, Fuessl., Mag. fur Liebhaberder Ent., vol. II, p. 286, 1778. 
Phalaena Bombyx dispar, De Geer, Abhl. Gesch. der Ins , vol. II, p. 293, 

1778. 
Phalaena Bombyx dispar, Goeze, Ent. Beit. Ritter, part III, vol. II, p. 

331, 1779. 
Phalaena dispar, Leske, Anfangs. Handb. Nat. Gesch., p. 460, No. 8, 1779. 
Eichen und Ulmraupe, Glazer, Abhl. von schiidl. Raupen, p. 39, 1780. 
Phalaena dispar, Rimrod, Naturforscher, vol. XVI, p. 130, 1781. 
Bombyx dispar, Fab., Species Insectorum, vol. II, p. 183, 1781. 
Bombyx dispar, Lang, Verz., p. 86, No. 661-664, 1782. 
Phalaena Bombyx Dispar, Esper, Schmett., vol. Ill, p. 197, pi. 38, figs. 

1-6, 1782. 
*Bombyx Dispar, Martin, Vade-Mecum, Pom. Trees, No. 44, 1785. 
Le zigzag, Ernst, Pap. d'Europe, vol. IV, p. 106, pi. 138, fig. 186, a-g, 1785. 
Phalaena dispar, Bock, Versuch. Nat. Gesch., etc., vol. V, pp. 29-32, 1785. 
*Fourc, Entomologia Parisiensis, p. 261, No. 14, 1785. 
Bombyx dispar, Fab., Mantissa Insectorum, vol. II, p. 117, 1787. 
Borowski, Naturgeschichte Theirreichs., vol. VII, p. 97, 1786. 
Borowski, Naturgeschichte Theirreichs., vol. VIII, p. 77, 1787. 
*De Villers, Ent. Linnaei, vol. II, p. 144, 1789. 
Bombyx dispar, Vieweg, Tab. Verzeichniss, vol. I, p. 54, 1789. 
Bombyx dispar, Lodi, Opuscol. scelt., vol. XII, p. 183, 1789. 
Bombyx Dispar, Borkh., Eur. Schm., vol. Ill, p. 312, No. 118, 1790. 
Bombyx disparate, Oliv. Ency. Meth., vol. Ill, p. -59, 1790. 
Rossi, Fauna Etrusca, vol. II, p. 170, 1790. 
Phalaena Bombyx Dispar, Preyssler, Verz. bomischer Insecten, p. 41, 

1790. 
Sepp, Nederlandische Insecten, vol. Ill, p. 5, pi. 2, 3, 1791 (?). 
Phalaena Bombyx Dispar, Schwarz, Raupenkalender, pp. 60, 224, 377, 1791. 
Phalaena Bombyx dispar, Brahm, Ins. Kal. II, p. 517, No. 378; p. 739, No. 

24, 1791. 
♦Hennert, Raupenfrass und Windbruch, 1791. 
Bombyx dispar, Borkh., Rhein. Mag., vol. I, p. 334, 1791-94. 
Bombyx dispar, Fab., Ent. Syst., vol. Ill, part I, p. 437, 1793. 
Phalaena Bombyx Dispar, Pezolds, Mitteldie una Schad., etc., vol. II, fig. 

8, 1794. 
Bombyx dispar, Panzer, Fauna Germ., vol. II, pp. 22, 23, 1794. 
Phalaena Dispar, Berk., Synop. Nat. Hist., Gr. Brit, and Ire., vol. I, p. 136, 
1795. 



BIBLIOGRAPHY. 259 

Phalaena Dispar, Don., Nat. Hist. Br. Ins., vol. V, p. 67, pi. 163 (Gipsey 

Moth). 1796. 
Bombyx Dispar, Hub., Samml. Bomb., p. 121, pi. 19, figs. 75 male, 76 

female, 1800 (?). 
Bombyx Dispar, Illiger's edition, Wien Verz., vol. I, p. 75, 1801. 
Laria dispar, Schrank, Faun. Boica, vol. II, part 1, p. 256; part 2, p. 151, 

1801-02. 
var. (?) a, Bombyx disparina, von Mueller, Fauna Silesiaca, part III, vol. 

I, 1802. 
♦Phalaena Bombyx dispar, Stewart, Elements of Nat. Hist., vol. II, p. 150, 

1802. 
Bombyx disparus, Haworth, Lep. Brit., p. 88, 1803. 

Phalaena dispar, Blumenbach, Manuel d'Histoire Nat., vol. I, p. 465, 1803. 
Stammphalane, Goeze, Naturgeschichte der Europais., vol. IX, p. 569, 

1803. 
Phalaena Bombyx Dispar, Bechstein, Forstinseckten, p. 369, pi. 6, fig. 1, 

a-e, 1804. 
Bombyx dispar, Panzer, Syst. Nomen., p. 40, 1804. 
Bombyx dispar, Latreille, Hist. Nat. des Crust, et Ins., vol. XIV, p. 185, 

1805. 
Bombyx Dispar, Linn., Syst. Nat., Turton edition, vol. Ill, p. 207, 1806. 
Bombyx Dispar, Hub., Ges. Europ. Schm., pi. 37, fig. 2, a, b, c, 1806-18. 
Liparis Dispar, Ochs., Schm. Eur., vol. Ill, p. 195, 1810. 
Phalaena Dispar, Blumenbach, Abbild. Nat. Hist. Gegenstand, p. 370, 1810. 
Bombyx disparate, Latreille, Crustaces, Arach. et Ins., pi. 8, fig. 2, 1810. 
Laria Dispar, Leach, New Edinburgh Ency., Article Entomology, p. 721, 

1815. 
Phalaena Dispar, Salisbury, Hints to Propr. of Orchards, p. 67, pi. 1, figs. 

10,11, 1816. 
Sericaria dispar, Latreille, Le Regne Animal, vol. II, p. 269 ; Atlas, pi. 152, 

1817. 
Bombyx disparate, Latreille, Le Regne Animal, vol. Ill, p. 568, 1817. 
Liparis Dispar, Zincken, Germar's Mag. der Ent., vol. Ill, p. 431, 1818. 
Liparis dispar, Samouelle, Ent. Com., p. 246 (Gipsey Moth), 1819. 
Liparis Dispar, Godart, Hist. Nat., vol. IV, p. 256, pi. 25, figs. 1, 2, 1822. 
Porthetria Dispar, Hub., Verz. bek. Schmett., p. 160, 1822 (?). 
Bombyce disparate, Dumeril, Considerat. General., pi. 45, fig. 3, 1823. 
♦Laria dispar, Meig., Handb. fiir Schm., p. 122, pi. 47, 1827. 
Hypogymna dispar, Daudville, Ann. Soc. d'Hort. Paris, vol. Ill, p. 98, 

1828. 
Hypogymna dispar, Daudville, Ann. Soc. d'Hort. Paris, vol. V, pp. 204, 

324, 1829. 
Bombyx dispar, J. M., Gardener's Mag., vol. V, p. 204, 1829. 
Hypogymna dispar, Steph., 111. Br. Ent. Haust., vol. II, p. 56, 1829. 
♦Liparis dispar, Klug., Verhandl. deGesell, Naturf. Freunde, pp. 363, 369, 

pi. 1, fig. 20, 1829. 
Hypogymna dispar, Steph., Cat. Ins. Haust., p. 50, 1829. 
Hypogymna dispar, Rennie.Libr. of Entert. Knowl., vol. II, pp. 79-82, 1830. 
Sericaria dispar, Latreille, Animal Kingdom, vol. IV, p. 201, 1831. 
Liparis dispar, Bdv., Coll. Icon, et Hist, des Chenilles d'Eur., pi. IX, figs. 

3, 4, 1832. 



260 THE GYPSY MOTH. 

Bombyx dispar, Brown, Book of Butterflies, vol. I, p. 52, 1832. 
♦Liparis dispar, Dup. et Gueu., Icon, de l'Hist. Nat. Chenilles, vol. II, pi. 

8, figs. 2-6, 1832. 
Liparis dispar, Godart, Icon, des Chenilles, les Bombycites, pi. 8, 1832. 
*Hypogymna dispar, Rennie, Conspectus of Butterflies and Moths, p. 39, 

1832. 
Phalaena Bombyx dispar, Anon., Ann. de l'lnst. Hort. Fromont, vol. V, 

p. 311, 1833. 
Liparis dispar, Silb., Revue Entomologique, ser. I, vol. I, p. 80, 1833. 
Liparis Dispar, Bouche, Nat. Gesch. der Ins., Lieberung I, p. 106, 1834. 
Liparis dispar, Burm., Manual of Entomology, p. 313, 1836. 
Hypogymna dispar, Duncan, Naturalist's Library, vol. IV, p. 206, 1836. 
Liparis dispar, Lacordaire, Manual of Entomology, p. 312, 1836. 
Bombyx dispar, Sepp, title-page, vol. V, aberr. male, 1836. 
Liparis dispar, De Selys, Cat. Lep. de la Belg., p. 28, 1837. 
Liparis dispar, Krause, Arbeit. Schles. Gesell. f. vaterl. Kultur, p. 110, 1837. 
Liparis dispar, Boie, Naturhistorisk Tidskrift, vol. I, p. 522, 1837. 
Liparis dispar, Audouin, Naturhistorisk Tidskrift, vol. II, p. 304, 1838. 
Liparis dispar, Lacordaire, Intro, a l'Entomologie, vol. II, pp. 371, 383, 

1838. 
♦Bombyce disparate, Debia, Rec. Agr. Soc. Dept., p. 156, pi. 1, 1838. 
Hypogymna dispar, Curt., Br. Ent., vol. XVI, p. 767 (Gypsy Moth), 1839. 
Bombyce disparate, Lamarck, Animaux sans Vertebres, vol. Ill, p. 77, 

1839. 
Bombyx dispar, Dejean, Ann. Soc. Ent. France, vol. VIII, p. 41, 1839. 
Bombyx dispar, Reichenbacka, Galerya, Obr. Zwier. Hist. Nat., vol. II, 

p. 302, 1839. 
Bombyx (Liparis) dispar, Nordl., Stett. Ent. Zeit.,vol. I, p. 266, 1840. 
Bombyx (Liparis) dispar, Kollar, Inj. Ins., English ed., p. 26, 1840. 
Phalaena Bombyx dispar, Ratz., Forst. Ins., vol. II, p. Ill, pi. 5, figs. 

IF, IF', IK, 1L, 1C, 1840. 
Liparis dispar, Schultze, Stett. Ent. Zeit., vol. I, p. 49, 1840. 
Hypogymna dispar, Westvv , Int. to Modern Classif. Ins., p. 384, 1840. 
Bombyx dispar, Fonscol., Mem. de l'Acad. de Sci. Agr. Arts, etc., vol. V, 

p. 85, 1840. 
Liparis Dispar, Hering, Stett. Ent. Zeit., vol. Ill, p. 9, 1842. 
Liparis dispar, Joly, Revue Zoologie, vol. V, p. 115, 1842. 
Porthetria dispar, Humphrey and Westw., Br. Moths and their Transf., 

vol. I, p. 17, figs. 1-3, 1843. 
Liparis Dispar, Duponchel, Cat. Methodique, p. 68, 1844. 
Liparis Dispar, Eversmanu, Fauna Lep. Volgo-Ural, p. 142, 1844. 
Liparis Dispar, Herrich-Schaeffer, Eur. Schm., vol. II, p. 135, 1845. 
Liparis dispar, Villa, Memoria deg Insetti carnivori, p. 59, 1845. 
Liparis dispar, Ratz., Stett. Ent. Zeit., vol. VII, p. 37, 1846. 
Liparis dispar, Bellier, Ann. Soc. Ent. France, vol. XVI, p. 98, 1847. 
Bombyx dispar, Johnson, Diet, of Modern Gardening, p. 92, 1847. 
Bombyx dispar, Nordl., Stett. Ent. Zeit., vol. IX, p. 266, 1848. 
Liparis dispar, Bellier, Bull. Soc. Ent. France, ser. II, vol. VII, p. 173, 

pi. 6, 1849. 
Liparis dispar, Guen., Hist. Nat. Nocturnes, vol. II, pi. 8, fig. 2, a, b, 1849. 
Liparis dispar, Bellier, Bull. Soc. Ent. France, ser. II, vol. X, p. 73, 1852. 
Liparis dispar, Filippi, Stett. Ent. Zeit., vol. XIII, p. 263, 1852. 



BIBLIOGRAPHY. 261 

Liparis Dispar, Speyer, Stett. Eat. Zeit., vol. XIII, p. 318, 1852. 
Lymantria dispar, Walk., Cat. Lep. Het., part IV, p. 872, 1855. 
Bombyx dispar, Sepp, title-page, vol. VIII, aberr. male, 1855-60. 
Liparis dispar, DeSelys (?), Ana. Soc. Eut. Belg., vol. I, p. 52, 1857. 
Hypogymna dispar, Stainton, Manual, vol. I, p. 130, 1857. 
Hypogymna Dispar, Humphrey, Gen. Br. Moths, p. 27, pi. 10, figs. 1-10, 

1858. 
Ocneria dispar, Speyer, Die Geograph. Verbreit. Schm., part I, p. 401, 

1858. 
Hypogymna Dispar, Kearley, Ent. Weekly Intelligencer, vol. IV, p. 192, 

1858. 
Rosenspinner, Hermann, Der Raupen und Schmetterlingsjiiger, p. 81, 1859. 
Liparis dispar, Hagen, Stett. Ent. Zeit., vol. XXI, p. 34, 1860. 
Liparis dispar, Leunis, Zoologie, p. 543, 1860. 
Hypogymna dispar, Batty, Ent. Weekly Intelligencer, vol. VIII, p. 141, 

1860. 
Hypogymna dispar, Stanley, Ent. Weekly Iutelligeucer, vol. VIII, p. 187, 

1860. 
Schwammspinner, Pueschl., Kurzgefasste Forst. Ency., Leipzic, pp. 186, 

298, 1S60. 
Liparis dispar, Mulder, Tijdschrift voor Ent., ser. I, vol. II, p. 2, 1860. 
Liparis dispar, Goreau, Ins. Nuis. aux Arbres Fruitiers, p. 89, 1861. 
Liparis dispar, Hagen, Stett. Eut. Zeit., vol. XXII, p. 59, 1861. 
Liparis Dispar, Rathke, Stett. Ent. Zeit., vol. XXII, p. 238, 1861. 
Bombyx dispar, Siebold, Stett. Ent. Zeit., vol. XXII, p. 443, 1861. 
Liparis dispar, Dobner, Zool., vol. II, p. 345, 1862. 
Ocneria dispar, Speyer, Die Geog. Verbreit. Schm., part II, p. 287, Nach- 

trage, 1862. 
Liparis dispar, Keller, Stett. Ent. Zeit., vol. XXIII, p. 284, 1862. 
Liparis dispar, Prittw., Stett. Ent. Zeit., vol. XXIII, p. 382, 1862. 
Liparis dispar, Newra., Proc. Ent. Soc. Lond., pp. 70, 77, 1862. 
Ocneria dispar, Jaggi, Bull. Soc. Eat. Suisse, vol. I, p. 313, 1862-65. 
Liparis dispar, Bremer, Lepidopteren Ost-Siberiens, p. 41, 1864. 
Liparis dispar, Bdv., Journ. Soc. Hort. France, p. 447, 1864. 
Sericaria dispar, Mulder, Tijdschrift voor Ent., ser. I, vol. VII, p. 125, 

1864. 
Liparis dispar, Keppen, Horae Soc. Ent. Rossicae, pp. 81, 257, 287, 294, 

1865. 
Ocneria dispar, Tieffenbach, Berl. Ent. Zeit., vol. IX, p. 413, pi. 3, flg. 8, 

1865. 
Bombyx dispar, Samuels, Agriculture of Mass., p. 116, 1865-66. 
Bombyx dispar, Ratz., Die Waldverderbniss, vol. I, pp. 113, 226, 1866. 
Ocneria dispar, Maurissen, Tijdschrift voor Ent., ser. II, vol. IX, p. 176, 

1866. 
Liparis dispar, Brehm and Rossmassler, Die Thiere des Walden, vol. II, 

p. 107, flg. 11 ; p. 108, figs, a-d, 1866-67. 
Ocneria dispar, Pfutzner, Berl. Ent. Zeit., vol. XI, p. 199, 1867. 
Liparis dispar, Westwood, Proc. Ent. Soc. Lond., pp. 44, 49, 1867. 
Ocneria dispar, de Gavere, Tijdschrift voor Ent., ser. II, vol. X, p. 200, 

1867. 
Bombyx dispar, Rudzky, Horae Soc. Ent. Rossicae, vol. V, p. 12, 1867. 
♦Ocneria Dispar, var. Disparina, Snell., Vlind. Nederl. Macro., p. 175, 1867. 



262 THE GYPSY MOTH. 

Liparis dispar, Bdv., Essai sur l'Entomologie Horticole, 1867. 

Bombyx dispar, Ratz., Die Waldverderbniss, vol. II, pp. 12-151, etc., 

1868. 
Bombyx dispar, Berce, Bull. Ent. Soc. France, ser. Ill, vol. VIII, p. 61, 

1868. 
Liparis dispar, Dorfmeister, Stett. Ent. Zeit., vol. XXIX, p. 183, 1868. 
Liparis dispar, Charault, Bull. Soc. Agr. Sci. Arts, vol. XI, pp. 688, 697, 

1868. 
Bombyx dispar, Senft, Systematische Bestimm. Deutsch., p. 77, pi. 1, 2, 

3, 5, 1868. 
Liparis dispar, Girard, Bull. Soc. Ent. France, ser. Ill, vol. IX, p. 69, 

1869. 
Liparis dispar, Bull, della Soc. Ent. Italiana, vol. I, p. 69, 1869. 
Bombyx dispar, Bull, della Soc. Ent. Italiana, vol. I, pp. 78-81, 1869. 
Liparis dispar, Charault, Bull. Soc. Agr. Sci. Arts of Sarthe, vol. XII, 

p. 316, 1869. 
Liparis Dispar, Kieferstein, Stett. Ent. Zeit., vol. XXX, p. 229, 1869. 
Ocneria dispar, Speyer, Stett. Ent Zeit., vol. XXX, p. 246, 1869. 
Phalaena Bombyx dispar, Ratz., Die Waldverderber, p. 184, pi. 5, fig. 1, 

1869. 
Liparis dispar, Newra., British Moths, p. 37, 1869. 
Ocneria dispar, Jaggi, Bull. Soc. Ent. Suisse, vol. Ill, p. 100, 1869-70. 
Hypogymna dispar, Riley, Annual Rep. Missouri, vol. II, p. 10, 1870. 
Hypogymna dispar, Riley, Am. Ent., vol. II, p. Ill, 1870. 
Liparis dispar, Bargagli, Bull, della Soc. Ent. Italiana, vol. II, pp. 208, 

262, 279, 1870. 
Bombyx dispar, Bazin, Bull. Soc. Hist, de l'Yonne, ser. I, vol. XXIV, pp. 

11-20, 1870. 
Ocneria dispar, Tratman, The Ent., vol. V, p. 172, 1870. 
Ocneria dispar, Spiller, The Ent., vol. V, p. 183, 1870. 
Ocneria dispar, Davidson, The Ent., vol. V, p. 213, 1870. 
Ocneria dispar, Button, The Ent., vol. V, p. 393, 1870. 
Ocneria dispar, Bowyer, The Ent., vol. V, p. 452, 1870. 
Ocneria dispar, Hylaerts, Tijdschrift voor Ent., ser. II, vol. XIII, p. 148, 

1870. 
Ocneria Dispar, Kirby, Cassell's Eur. But. and Moths, p. 110, pi. 25, figs. 

a-c, 1870 (?). 
Liparis dispar, Briggs, Proc. Ent. Soc. Lond., p. 9, 1871. 
Liparis dispar, Dohrn, Stett. Ent. Zeit., vol. XXXII, p. 29, 1871. 
Liparis dispar, Dei, Bull, della Soc. Ent. Italiana, vol. Ill, pp. 75, 360, 

1871. 
Ocneria dispar, Hylaerts, Tijdschrift voor Ent., ser. II, vol. XIV, p. 38, 

1871. 
Bombyx dispar, Siebold, Bull, della Soc. Ent. Italiana, vol. IV, p. 121, 

1872. 
Liparis dispar, Plateau, Bull, della Soc. Ent. Italiana, vol. IV, p. 197, 1872. 
Liparis dispar, Vinercati, Bull, della Soc. Ent. Italiana, vol. IV, p. 302, 

1872. 
Liparis dispar, Ghiliani, Bull, della Soc. Ent. Italiana, vol. IV, p. 365, 

1872. 
Liparis dispar, Lelievre, Feuilles des Jeunes Naturalistes, vol. Ill, p. 77, 
1872. 



BIBLIOGRAPHY. 263 

Ocneria dispar, Hagen, Stett. Ent. Zeit., vol. XXXIII, p. 389, 1872. 
Ocneria dispar, Nickerl., Verh. z. B. Wien., vol. XXII, p. 729, 1872. 
Phalaena Bombyx dispar, Kauschinger, Die Lehre vom Walds., p. 65, flg. 

13, 1872. 
Liparis dispar, Greville, The Ent., vol. VI, p. 190, 1872. 
Liparis dispar, Clifford, The Ent., vol. VI, p. 289, 1872. 
Liparis dispar, Standish, The Ent., vol. VI, p. 364, 1872. 
Psilura dispar, Frey and Wullsch., Bull. Ent. Soc. Suisse, vol. IV, p. 258, 

1873-76. 
Ocneria dispar, Kigg.-Stehlin, Bull. Ent. Soc. Suisse, vol. IV, p. 597, 

1873-76. 
Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. V, p. 164, 1873, 
Ocneria dispar, Dihrik, Stett. Ent. Zeit., vol. XXXIV, p. 114, 1873. 
Liparis dispar, Kaltenbach, Die Pflanzenfeinde, pp. 74, 158, 185, 205, 217, 

429, 1874. 
Ocneria dispar, Kaltenbach, Die Pflanzenfeinde, pp. 537, 548, 569, 594, 

613, 626, 634, 640, 651, 1874. 
♦Liparis dispar, Barrett, Trans. Norwich Soc, suppl., p. 14, 1874. 
Liparis dispar, Plateau, Recherches sur Digestion, etc., p. 84, 1874. 
Bornbyx (Liparis) dispar, Tasch., Ent. f. Giirt. und Garten, p. 219, figs. 

58-61, 1874. 
Liparis dispar, Targ. Tozz., Bull, della Soc. Ent. Italiana, vol. VI, p. 86, 

1874. 
Liparis dispar, Dubois, Lep. de Belgique, vol. II, p. 170, 1874. 
Ocneria dispar, Lelievre, Feuilles des Jeunes Naturalistes, vol. V, pp. 

97-100, 1874. 
Liparis dispar, Girard, Bull. Soc. Ent. France, suppl., vol. IV, p. 129, 1874. 
Liparis dispar, Girard, Bull. Soc. Ent. France, suppl., vol. V, p. 114, 1875. 
Liparis dispar, Gaschet, Bull. Ent. Soc. France, ser. V, vol. V, p. ccxiii, 

1875. 
Chenilles a oreilles, Ernst, Pap. de l'Europe, vol. IV, p. 106, pi. 138, 1875. 
Liparis dispar, Villa, Lo. Studio Insetti in Lombardia, 1876. 
Bombyx dispar, Blanchere, Rav. des For. et Arbres d'Align., pp. 178, 853, 

figs. 92, 93, 153, 154, 155, 156, 1876. 
Ocneria dispar, Weithofer, Verh. ver Briinn., vol. XV, p. 39, 1876. 
Liparis dispar, var. b, bordigalensis or disparoides, Mab. and Gasch., Bull. 

et Ann. Soc. Ent. France, ser. V, vol. VI, pp. 9, 521, 1876. 
Liparis dispar, Mabille, Bull. Soc. Ent. France, suppl., vol. VI, p. 9, 1876. 
Ocneria dispar, Bettoni, Considerazioni sopra casa, etc., p. 121, 1876. 
Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. VIII, p. 129, 

1876. 
Liparis dispar, Brehm, Thierleben, vol. IX, p. 15, 1877. 
♦Bombyx dispar, Bouche, Schwammraupe, Schvvammspinner, vol. IV, p. 
410, 1877. 
Liparis dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. IX, p. 55, 1877. 
Liparis dispar, Depuisset, Les Paps., p. 248, pi. 24, flg. 2, a-c, 1877. 
Ocneria dispar, Christoph., Stett. Ent. Zeit., vol. XXXIX, p. 408, 1878. 
Ocneria Dispar, Cassel, Die Makrolep. der Amgegend Cassels, p. 113, 1878. 
Ocneria dispar, Brants, Tijd. Ent., vol. V, p. 22, 1878. 
Liparis dispar, Locard, Soc. Agr. Sci. and Arts of Lyons, 1878. 
Ocneria dispar, Enock, The Ent., vol. XI, p. 170, 1878. 
Ocneria dispar, Rondani, Bull, della Soc. Ent. Italiana, vol. X, p. 22, 1878. 



264 THE GYPSY MOTH. 

Ocneria dispar, Turati, Bull, della Soc. Ent. Italiana, vol. XI, p. 171, 1879. 
*Dickkopfspinner, Hommerling, Isis, Russ., vol. IV, p. 86, 1879. 
*Liparis dispar, Szalkay, Termeszet, Fuzetek, vol. IV, p. 105, 1879. 

Liparis dispar, Pearce, The Ent., vol. XII, p. 229, 1879. 

Bombyx dispar, Altum, Forstzoologie, vol. II, p. 324, 1880. 

Psilura Dispar, Freyer, Lep. der Schweiz., p. 94, 1880. 
*Liparis dispar, Slosarski, Der Polnische Gartner, vol. II, pp. 69-92, 1880. 

Liparis dispar, Wilson, Larvae of the Brit. Lep., p. 68, pi. 12, fig. 8, 1880. 

Ocneria dispar, Fiori, Bull, della Soc. Ent. Italiana, vol. XII, p. 214, 1880. 

Ocneria dispar, Maassen, Stett. Ent. Zeit., vol. XLI, p. 168, 1880. 

Ocneria dispar, Hering, Stett. Ent. Zeit., vol. XLII, p. 334, 1881. 

Ocneria dispar, Staudinger, Stett. Ent. Zeit., vol. XLII, p. 406, 1881. 

Bombyx (Liparis) dispar, Schm-Gobel, Die Schadlichen Forstinseckten, 
part I, p. 99, fig. 95, 1881. 

Bombyx (Liparis) dispar, Schm-Gobel, Die Schadlichen Forstinseckten, 
part II, p. 96, 1881. 

Bombyx dispar, Altum, Forstzoologie, vol. II, p. 324, 1881. 

Liparis dispar, Goossens, Bull. Ent. Soc. France, vol. I, p. 232, 1881. 

Liparis dispar, Lucas, Bull. Ent. Soc. France, vol. I, p. 148, 1881. 

Liparis dispar, Girard, Bull. Ent. Soc. France, vol. II, 1882. 

Ocneria dispar, Gauckler, Katter's Ent. Nachtrichteu, vol. VIII, p. 274, 
1882. 

Liparis dispar, Altum, Forstzoologie, vol. Ill, p. 94, 1882. 

Ocneria dispar, Teich., Stett. Ent. Zeit., vol. XLIV, p. 171, 1883. 

Ocneria dispar, Keppen, Injurious Insects, vol. Ill, p. 49, 1883. 

Ocneria dispar, Mina, Naturalista Sicil. Giorna. Sci. Nat., vol. Ill, p. 54, 
1883. 

Ocneria dispar, Oudemans, Tijd. Ent., vol. XXVII, p. 16, 1884. 

Ocneria Dispar, Homeyer, Stett. Ent. Zeit., vol. XLV, p. 424, 1884. 

Ocneria dispar, Tasch., Brehm's Thierleben, Inseckten, p. 395, figs. 1-3, 
1884. 
♦Ocneria dispar, Kalchberg, Naturalista Sicil. Giorna. Sci. Nat., vol. IV, 
p. 55, 1884-85. 

Hypogymna dispar, "Wood, Animated Creation, vol. Ill, p. 423, 1885. 

Ocneria dispar, Bull, della Soc. Ent. Italiana, vol. XVII, p. 156, 1885. 

Ocneria dispar, Raynor, The Ent., vol. XVIII, p. 243, 1885. 

Ocneria dispar, St. John, The Ent., vol. XIX, p. 250, 1886. 

Ocneria dispar, Adkin, The Ent., vol. XIX, p. 281, 1886. 

Ocneria dispar, Blaber, The Ent., vol. XIX, p. 281, 1886. 

Ocneria dispar, Hall, The Ent., vol. XIX, p. 282, 1886. 

Ocneria dispar, Buckler, Larvae of Brit. Butterflies, vol. Ill, p. 37, 1886. 

Liparis dispar, Brocchi, Traite de Zoologie Agricole, p. 451, 1886. 

Ocneria dispar, ab. semiobscura, Thierry, Le Naturalist, vol. VIII, p. 237, 
1886. 

Ocneria dispar, ab. erebus, Thierry, Le Naturalist, vol. VIII, p. 237, 1886. 

Ocneria dispar, ab. semiobscura, Meig., Le Naturalist, vol. VIII, p. 237, 
1886. 

Ocneria dispar, ab. erebus, Meig., Le Naturalist, vol. VIII, p. 237, 1886. 

*The Gypsy Moth, Dictionary of Gardening (Insects), vol. II, p. 182, 1887. 

Ocneria dispar, Edwards, The Ent., vol. XX, p. 275, 1887. 

Liparis dispar, Goossens, Bull. Ent. Soc. France, ser. VI, vol. VII, p. 166, 
1887. 



BIBLIOGRAPHY. 2G5 

Liparis dispar, Bellier, Bull. Ent. Soc. France, ser. VI, vol. VII, p. 182, 

1887. 
Ocneria (Liparis) dispar, Hess, Der Forstschutz. , ed. II, vol. II, pp. 70-75, 

fig. 53, a-d, 1887. 
Ocneria dispar, Theile, Berl. Ent. Zeit., vol. XXXI, p. 23, 1887. 
Ocneria dispar, Mina, Naturalista Sicil. Giorn. Sci. Nat., vol. VII, p. 225, 

1887-88. 
Ocneria Dispar, Graeser, Berl. Ent. Zeit., vol. XXXII, p. 125, 1888. 
Ocneria Dispar, Ziegler, Berl. Ent. Zeit., vol. XXXII, p. 23, 1888. 
* Liparis dispar, Oliv , Rev. Sci. Bourb., vol. I, p. 210, 1888. 
Ocneria dispar, Bock, Ent. Nachr., vol. XIV, p. 56, 1888. 
Ocneria dispar, Jackson, The Ent., vol. XXI, pp. 235, 322, 1888. 
Ocneria dispar, Walk., Ent. Mon. Mag., vol. XXV, p. 65, 1888. 
Lymantria dispar, Leech, Proc. Zool. Soc. Lond., vol. LVI, pp. 30, 63, 

1888. 
Liparis dispar, Platner, Biol. Centralbl., vol. V, p. 521, 1888. 
*Schwammspiuner, Katzer, Zum Frasse des Schwammsp. in Kroatien, 

1888-89. 
Borabyx (Liparis) dispar, Fiirst, Kauchinger's Lehre von "Walds., ed. 4, 

pp. 140, 141, pi. 3, 1889. 
Liparis (Ocneria) dispar, Targ. Tozz., Bull, della Soc. Ent. Ital., vol. 

XXI, pp. 113, 272, 1889. 
Ocneria dispar, Cune, Act. Soc. Esp., vol. XVIII, p. 77, 1889. 
Ocneria dispar, Berge, Schmett., p. 63, pi. 26, fig. 2, a-c, 1889. 
Ocneria dispar, Porchinsky, Ins. Inj. to Fruit Gardens, Crimea, pp. 14-20, 

1889. 
Liparis dispar, Tunley, The Ent., vol. XXII, p. 259, 1889. 
Ocneria dispar, Hall, The Ent., vol. XXII, p. 161, 1889. 
Ocneria dispar, St. John, The Ent., vol. XXII, p. 162, 1889. 
Ocneria dispar, Arkle, The Ent., vol. XXII, p. 186, 1889. 
Ocneria dispar, Fernald, Mass. Hatch Exp. Station, Special Bulletin, 1889. 
Hypogymna dispar, Buck, Larvae Brit. Moths, pi. 37, figs. 6, 6a, 1889. 
Ocneria dispar, Howard, Proc. Ent. Soc. Wash., vol. I, p. 264, 1889. 
Ocneria dispar, Dei, Bull, della Soc. Ent. Ital., vol. XXII, p. 276, 1890. 
Ocneria dispar, Wingelmuller, Mem. 111. Garten Zeitung, p. 269, 1890. 
Liparis Dispar, Raspail, Bull. Soc. Zool. France, vol. XV, p. 94, 1890. 
Liparis dispar, Montillot, Amateur d'lusectes, p. 252, 1890. 
The Gypsy Moth, Rep. Mass. Bd. Agr., p. 58, 1890. 
Ocneria dispar, Ent. Record, vol. I, p. 225, 1890. 
Ocneria dispar, Ent. Record, vol. II, p. 24, 1890. 
Ocneria dispar, Pack., Rep. U. S. Ent. Com., vol. V., p. 138, 1890. 
The Gypsy Moth, Sargent, Garden and Forest, vol. Ill, p. 150, 1890. 
Gypsy Moth, Jack, Garden and Forest, vol. Ill, pp. 273, 277, 1890. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. II, pp. 86, 208, 262, 1890. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. Ill, pp. 41, 78, 126, 1890. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. Ill, pp. 200, 297, 364, 

368, 381, 472, 474, 491, 1891. 
Ocneria dispar, Lintn., Rep. Ins. N. Y., vol. VII, pp. 302, 304, 335, 357, 

1891. 
Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 289, 1891. 
Ocneria dispar, Butler, Ins. Life, vol. Ill, p. 277, 1891. 
Ocneria dispar, Weir, Ins. Life, vol. IV, p. 138, 1891. 



266 THE GYPSY MOTH. 

The Gypsy Moth, Jack, Garden and Forest, vol. IV, p. Ill, 1891. 
The Gypsy Moth, Fernow, Garden and Forest, vol. IV, p. 142, 1891. 
The Gypsy Moth, Smith, Garden and Forest, vol. IV, p. 153, 1891. 
Bombyx (Liparis) dispar, Demaison, Bull. Ent. Soc. France, vol. LX, p. 

14, 1891. 
Liparis dispar, Bezzi, Bull, della Soc. Ent. Ital., vol. XXXIII, p. 74, 

1891. 
Ocneria dispar, de Muro, Bull, della Soc. Ent. Ital., vol. XXXIII, p. 328, 

1891. 
Ocneria dispar, Ent. Record, vol. Ill, pp. 53, 183, 1891. 
Ocneria dispar, Fernald, Mass. Hatch Exp. Sta., Bull. 19, p. 109, 1892. 
Ocneria dispar, Fernald, Can. Ent. vol. XXIV, p. 87, 1892. 
Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 259, 1892. 
Ocneria dispar, Henshaw, U. S. Dept. Agr., Bull. 26, p. 75, 1892. 
The Gypsy Moth, Jack, Garden and Forest, vol. V, p. 75, 1892. 
The Gypsy Moth, S., Garden and Forest, vol. V, p. 81, 1892. 
The Gypsy Moth, Nutter, Garden and Forest, vol. V, p. 119, 1892. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. IV, pp. 227, 356, 1892. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. V, pp. 54, 194, 1892. 
Ocneria dispar, Hertwig, Text Book of Embryology, translated by Mark, 

p. 34, 1892. 
Ocneria dispar, Bethune, Rep. Ent. Soc. Ont., vol. XXIII, p. 86, 1892. 
Gypsy Moth, Beddard, Animal Coloration, p. 272, fig. 36, 1892. 
Ocneria dispar, Ent. Record, vol. Ill, pp. 699, 869, 1892. 
Ocneria dispar, Ent. Record, vol. IV, p. 204, 1892. 
Porthetria Dispar, Kirby, Cat. Lep. Het., vol. I, p. 475, 1892. 
Ocneria dispar, de Carlini, Bull, della Soc. Ent. Ital., vol. XXIV, p. 86, 

1892. 
Ocneria dispar, South, The Ent., vol. XXV, p. 259, 1892. 
Ocneria dispar, Hodkinson, The Ent., vol. XXVI, p. 20, 1893. 
Ocneria Dispar, Hofman, Die Raupen der Gross-Schmett., p. 57, pi. 16, 

fig. 13, 1893. 
Ocneria dispar, Eckstein, Die Kiefer, vol. I, p. 22, pi. 13, figs. 4-9, 1893. 
Bombyx (Liparis) dispar, Fiirst and Nisbet, Prot. of Woodlands, Eng. ed., 

pp. 126, 207, pi. 3, fig. 19, 1893. 
Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., p. 263, 1893. 
Ocneria dispar, Lintn., Rep. Ins. N. Y., vol. IX, pp. 422, 433, 440, 1893. 
Liparis dispar, Judeich and Nitsche, Lehrbuck der Mit.-Europ. Forstin- 

seckt., vol. Ill, 1893. 
Ocneria dispar, Seitz, Stett. Ent. Zeit., vol. LIV, p. 369, 1893. 
Ocneria dispar, Riley and Howard, Ins. Life, vol. VI, pp. 53, 235, 338, 

1893. 
Ocneria dispar, Skinner, Ent. News, vol. IV, p. 158, 1893. 
Porthetria dispar, Dyar, Proc. Bos. Soc. Nat. Hist., vol. XXVI, p. 155, 

1893. 
Ocneria dispar, Weed, Am. Nat., vol. XXVII, p. 750, 1893. 
Ocneria dispar, Kingsley, Am. Nat., vol. XXVII, p. 1070, 1893. 
Ocneria dispar, Nicholson, Ent. Record, vol. V, pp. 236, 310, 1893. 
Ocneria dispar, Weed, N. H. Coll. Ag. Exp. Sta., Bull. 23, p. 30, 1894. 
Hypogymna dispar, Barrett, Lep. Brit. Islands, part XX, p. 303, 1894. 
Ocneria dispar, Furneaux, Butterflies and Moths, p. 227, 1894. 
Ocneria dispar, Kulagin, Ins. Inj. to Gard. and Orchards in Russia, 1894. 



DISTRIBUTION IN THE OLD WOKLD. 267 

Ocneria dispar, Eudzky, Ins. Useful and Inj. to Fruit Trees, pp. 9-13, 

1894. 
Ocneria dispar, Kane, The Ent., vol. XXVII, p. 15, 1894. 
Ocneria dispar, South, The Ent., vol. XXVII, p. 25, 1894. 
Ocneria dispar, Turner, The Ent., vol. XXVII, p. 153, 1894. 
Ocneria dispar, Forbush and Fernald, Rep. Mass. Bd. Agr., 1894. 
The Gypsy Moth, Ent. Record, vol. VI, p. 314, 1895. 
The Gypsy Moth, Ent. Record, vol. VII, p. 146, 1895. 
Ocneria dispar, Mocsary, Termeszet. Fuzetek, vol. XVIII, pp. 67, 72, 

1895. 
Portlietria dispar, Comstock, Manual for the Study of Insects, p. 312, fig. 

378, 1895. 
Ocneria dispar, Fletcher, Rep. Ent. Soc. Ont., vol. XXV, p. 67, 1895. 
The Gypsy Moth, Fletcher, Trans. Royal Soc. Can., vol. I, p. 14, 1895. 
Ocneria dispar, Meyrick, Handbook of British Lepidoptera, p. 175, 1895. 

Distribution in Other Countries. 

The gypsy moth has a wide distribution in the old world. 
Speyer, in ' ' Die Geographische Verbreitung der Schmetter- 
linge," published in 1858-62, Vol. I, page 401, and Vol. II, 
page 287, informs us that it extends over the entire region, 
from the lowlands to the highlands, through middle and 
southern Europe, western Asia and northern Africa, reach- 
ing from Stockholm on the north to Algiers on the south, 
England on the west, the Altai Mountains and the Caspian 
Sea on the east. It extends also into eastern Asia, including 
Japan ; and the tropics, Neitner having found it in Ceylon. 

Bremer, in his " Lepidopteren Ost-Siberiens," published 
in 1864, reported it in south-eastern Siberia. Staudinger, 
in his "Catalog der Europa?ischen Faunengebiets," published 
in 1871, gives for the distribution of the gypsy moth the 
entire territory, except the northern countries, including 
southern Sweden and England. He also doubtfully includes 
Livonia. Grseser states that the young caterpillars of this 
species were very common in the early part of June, 1881, 
near Vladivostock, Siberia. He further states that the cater- 
pillars in Amoor have a very different appearance from those 
in Europe, the prevailing color being yellow ; but all the 
moths bred from these caterpillars were entirely like those 
of Europe, "Berlin Ent. Zeits.," Vol. XXXII. In 1861, 
Homeyer reported the gypsy moth on the Island of Majorca 
in great abundance, destroying both deciduous and evergreen 
trees. In the "Entomologist's Monthly Magazine," Vol. 



268 THE GYPSY MOTH. 

XXV, page 65, 1888, Mr. J. J. Walker reported that he 
found this insect in great abundance in southern Spain, near 
the village of Los Barrios. In a work on "Injurious In- 
sects," by Theodore Keppen, published in Russian and trans- 
lated for me by Dr. F. B. Stephenson, U. S. N., it is stated 
that this insect occurs in the central and southern parts of 
Russia, in the Caucasus and all southern Siberia, but it does 
not occur in the vicinity of St. Petersburg. He further states 
that, according to Nolken, it does not appear in the Baltic 
Provinces, but has been found occasionally in Livonia, and, 
on the authority of Albrecht, it is very common in the 
vicinity of Moscow. Roinanoft*, in the sixth volume of his 
" Memoires sur les Lepidopteres," reports it in North China, 
and I have in my collection three male gypsy moths from 
Pekin, China, received from Dr. O. Staudinger. In a letter 
from Dr. Ritzema-Boz of Holland, dated Sept. 3, 1895, he 
writes, "This insect is common in Holland and also in all 
western Europe." 

The Gypsy Moth in England. 

The earliest information that I have found of the presence 
of the gypsy moth in England, is given by Wilkes, in his 
work entitled "Twelve New Designs of Eno-lish Butterflies," 
published in London in 1741-42, with twelve plates, but with- 
out text. Plate X, Fig. 2, represents the insect under the 
name "The Gipsey Moth." 

Harris described it in his " Aurelian's Pocket Companion," 
published in 1775. Donovan, in his "Natural History of 
British Insects," Vol. V, published in 1796, figures this insect 
on Plate CLXIII, and describes it on pages 67-69, calling 
it the "Gipsey Moth." In his account he says : "That the 
Phalena Dispar was not uncommonly scarce about fifteen 
years ago, is evident from this circumstance, few collections 
of British insects that were in the hands of eminent collec- 
tors are without an English specimen, which was procured 
about that time." From his further account we infer that 
he considered it a rare insect in England. Ha worth, in his 
"Lepidoptera Britannica," page 88, published in 1803, calls 
it Bombyx disparus, and for a common name "The Gipsy," 
and says it is very rare. Salisbury, in his "Hints to Pro- 



THE GYPSY MOTH IN ENGLAND. 269 

prietors of Orchards," published in London in 1816, gives 
the fullest and most complete account of the gypsy moth that 
I have seen in English up to that date. He states that this 
caterpillar is common in gardens and woods, where it does 
considerable damage. 

Stephens, in Vol. II, page 56, "Illustrations of British. 
Entomology," Haustellata, 1829, says it is not common near 
London, but appears to abound in the fens of Huntingdonshire. 
He also refers to the statement that it was introduced into 
Britain by eggs imported by Mr. Collinson, but says that the 
abundance with which it occurs near Whittlesea, and the dis- 
similarity of the indigenous specimens (which are invaria- 
bly paler, with stronger markings) to the foreign, sufficiently 
refute the opinion. 

Curtis, in his "British Entomology," Vol. XVI, 1839, 
alludes to the scarcity of this species in the time of Donovan, 
and speaks of finding them in considerable numbers, when a 
boy, in the marshes at Horning, in Norfolk. Mr. Stainton, 
in his "Manual of Butterflies and Moths," Vol. I, page 130, 
1857, says, "It is found plentifully in fenny districts, but is 
not generally common." George Kearley, in the "Ento- 
mologist's Weekly Intelligencer," Vol. IV, page 192, 1858, 
speaks of the gradual disappearance of the gypsy moth in 
England, and states that it was claimed by some to have 
actually become extinct in that country. Mr. Eichard South, 
in the " Entomologist," Vol. XXV, page 259, 1892, states 
that entomologists in 1870 seem to have been a little troubled 
about the right of the gypsy moth to be considered a British 
insect, referring, of course, to those caterpillars or imagoes 
which were then found at large. He further says, after speak- 
ing of specimens having been found from time to time, that 
there is no reasonable doubt that this species is extinct in 
England; "that somewhere about the fourth decade of this 
century, the species began to decrease in numbers, and that 
toward the end of the fifties it had practically ceased to exist 
as a wildling in this country." 

Numerous attempts have been made to introduce this insect 
into England again, but they do not appear to have been 
successful. Many entomologists have bred it in confinement, 
continuing until it can now be regarded only as a semi-do- 



270 THE GYPSY MOTH. 

inesticated species in England ; and complete degeneration of 
the stock, by the process known as "in-and-in breeding," is 
possibly averted by the periodical introduction of eggs from 
the Continent. 

The late Mr. J. Jenner Weir, in a letter to " Insect Life," 
Vol. IV, page 138, 1891, said that the gypsy moth had been 
unintentionally exterminated in England, and further writes, 
" I think the gypsy moth must have been destroyed simply 
by collectors." Mr. C. G. Barrett, in his " Lepidoptera of 
the British Islands," Vol. II, page 303, 1894, gives a very 
good history of the occurrence of this moth in England and 
of its probable disappearance, but without assigning any 
cause for such disappearance. 

Mr. C. Nicholson read a paper on the life-history of the 
gypsy moth, before the City of London Entomological and 
Natural History Society, Sept. 18, 1894, in which he pro- 
posed for discussion, among others, the question why this in- 
sect had become extinct in England. Mr. J. W. Tutt gave it 
as his opinion that it was because the insect was not a native. 
" Its whole history proved it to be an imported species, even 
when it first became known. Thousands of specimens in all 
stages had been set loose in various parts of the country, 
but, with the exception of an odd specimen here and there, 
no specimens were taken wild. Its abundance in the fens for 
a year or two simply pointed to the care with which it was 
put out, and to the temporary existence of favorable condi- 
tions. There are thousands of acres of land, to all intents 
and purposes fitted for its establishment here, but it — pos- 
sibly the agriculturists would say fortunately — will not 
establish itself." 

The history of the gypsy moth in the United States does 
not seem to lend force to the view taken by Mr. Tutt, as 
much as we wish it might prove true, for it seems to thrive 
as well here as in any part of the old world. America is 
indebted to Europe for a long list of insect pests, many of 
which are far more injurious, because of their unrestricted 
increase, than in their native country ; notable among these 
are the currant saw-fly (JVematus ribesii), the larch saw-fly 
(Nematus erichsonii) , the cabbage butterfly (Pieris rapoe), 
the Buffalo carpet-beetle (Anthrenus scropkularice) and many 



THE GYPSY MOTH IN ENGLAND. 271 

others, none of which show any indications of a decline in a 
foreign country. The idea of Mr. Weir, that they were de- 
stroyed in England by collectors, hardly seems worthy of 
consideration. I will not attempt to express an opinion as to 
the cause of their extinction in that country, but it seems 
to me that it must be due to causes not yet understood ; and 
if the profound thinkers in entomological matters, of whom 
England has so many, have not satisfactorily settled this 
question, it would be folly for me to express any decided 
opinion on the subject. I wish, however, to call attention 
to one or two points. Great Britain, because of its insular 
position, the prevailing winds and the currents in the sur- 
rounding ocean, has a far different climate from that of 
Massachusetts or the interior of Europe and other parts of 
the old world, where this insect is usually most abundant. 
I noticed, when in England, that the foliage of all vegetation 
seemed darker than in this country, or, at least, than in the 
eastern part of it ; and it occurred to me that this might be 
due, in part, to the larger amount of moisture in the atmos- 
phere, especially as quite similar conditions of climate, with 
darker foliage occur in British Columbia, as I have been in- 
formed by my colleague, Mr. E. H, Forbush, who also states 
that the arboreal animals of that region are much darker than 
those in the eastern parts of the United States. Some years 
ago, while in England, my kind friend, Mr. C. G. Barrett, 
gave me a very complete series of British Tortricids, and 
I never look at my collection without noticing how much 
darker these insects are than the same species from Germany 
and other parts of Europe. It seems to me that this dark- 
ening may have resulted from natural causes, operating 
through a very long period of years. When these insects 
first made their way into the British forests and fens, with 
their darker surroundings, the lighter colored individuals, 
contrasting the most with the objects on which they rested, 
naturally fell a prey to their enemies more readily than the 
dark-colored individuals ; the darker ones were left to propa- 
gate the species, and, in time, a dark race was formed. I 
am well aware that I am now trespassing on ground which 
is far better understood by my English brethren, but I trust 
that I may be permitted to call attention to this matter for 



272 THE GYPSY MOTH. 

the purpose of considering the bearing of environment and 
climate on the gypsy moth. 

If we suppose that the native home of this insect was in 
central Europe or south-western Asia, and that it was de- 
veloped from some progenitor in which the sexes were of the 
same color, possibly not very unlike the males of the present 
time, we may well suppose that, as the females developed 
a larger number of eggs, rendering them so heavy that they 
flew but rarely, and, in time, not at all, their wings, not being 
used, would grow weaker and less useful as organs of flight, 
as we now find them. Under these circumstances, suppose 
them to be inhabiting trees and shrubs, the bark of which is 
of light color, as birch, their enemies, the birds, etc., could 
readily distinguish these strongly contrasting females on the 
trunks of the trees and destroy the darker forms, leaving 
the lighter examples to propagate the species ; and, as this 
went on, in time permanently light-colored females would be 
produced. 

The males fly actively during the day, and are captured, 
while on the wing, by insectivorous birds ; but in this case 
slight variations in color would not be apparent to the birds, 
and no discrimination would be made in favor of such vari- 
ations. For this reason the males have probably retained 
more of their primitive color and appearance, while the 
females have made a most remarkable change ; and, as a 
result, this insect furnishes a most striking illustration of 
what is called sexual dimorphism. 

Another reason for thinking that the males have changed 
far less than the females, and that the changes made were 
perhaps in a different direction, is the fact that they more 
nearly resemble the males of allied species than they do the 
females of their own. Compare Figs. 3 and 4, on Plate I., 
with Figs. 11, 14 and 17, on Plate 39, and also with Figs. 1 
and 2, on Plate I. The three species of Orgyia just referred 
to have wingless females (one of which, O. leucostic/ma, is 
represented on Plate 39, Fig. 18), which are so heavy that 
it would be impossible for them to fly with wings of ordinary 
size. It is probable, however, that the remote ancestors of 
these insects were winged in both sexes, and that, as the female 
developed a larger reproductive system and more eggs, she 



INJURIES IN THE OLD WORLD. 273 

became too heavy for flight, and at last abandoned all at- 
tempts, just as the gypsy moth is now doing, and that by dis- 
use these organs became atrophied, and nothing now remains 
but mere rudiments of the wings. A similar fate possibly 
awaits the gypsy moth. Two of the species of Orgyia, 
figured on Plate 39, Figs. 14 and 17, are so-called natives 
of this country; while the other, Fig. 11, is a native of 
Europe, and has been in this country probably a compara- 
tively short time, not long enough, at any rate, for the new 
environment to produce any noticeable change. Since the 
introduction of O. dejinita (Fig. 14) and 0. leucostigma into 
this country, whenever and in whatever way that may have 
happened, the three species have been in an environment 
which has produced marked changes in the males, while the 
wingless females have probably changed far less. The two 
American species have changed so little from each other that 
O. definite,, for a long time, was not recognized as a distinct 
species. It may have branched oft* from the stem of leucos- 
tigma at a comparatively recent date. 

If, in comparatively recent times, the gypsy moth made its 
way into England, by the help of man or otherwise, may not 
the darker color of the foliage and other surroundings have 
rendered the female moths more conspicuous objects to their 
enemies, so that, " in the struggle for existence," this species 
was exterminated before it had time to take on the darker 
colors, as may have been the case with the British Tortri- 
cids ? It may be thought that the warm, damp climate of 
England would favor fungoid plants which are destructive to 
insect life ; but, if this caused the extermination of the gypsy 
moth in England, why has it not also caused the extermi- 
nation of numerous other species with more or less similar 
larval habits? If any of the above conditions caused the 
extinction of this moth in England, we have little to hope 
for in America, since so very little of our territory has any 
such climatic conditions as England. 

Injuries in the Old World. 
There are many accounts, in the older books, of extensive 
damage done by insects at different times in various parts 
of Europe, some of which was probably caused by the gypsy 



274 THE GYPSY MOTH. 

moth ; but it is impossible to be quite sure what insects may- 
have been referred to in these old accounts for the reason 
that only local common names were used before 1758, when 
Linnaeus introduced the custom of giving a scientific name 
to each insect, by which it should be known in all countries. 
In a work entitled " Beschreibung von allerlei Insecten in 
Teutschland," by J. L. Frisch, published in Berlin, 1720, 
Vol. I, page 14, is a brief notice of a garden and forest 
caterpillar which is evidently the gypsy moth. Plate III 
represents a male, a female laying her eggs, a caterpillar, 
the anterior and posterior ends of a caterpillar and a male 
antenna. He writes of this insect as follows: "This cat- 
erpillar, in the third part of the copper-plate, Fig. 1, is 
called Bunt-Knopffig, on account of the light violet-blue 
and purple-red tubercles on its back, and also Garten und 
Forstraupe (garden and forest caterpillar), because it not 
only destroys all the leaves of the fruit-bearing trees of the 
orchard, but also does not hesitate to attack forest trees, 
especially the oaks, on which it is found every year. In this 
year, 1720, this caterpillar entirely stripped every tree of 
the double row of lindens along the road from Neustadt to 
Berlin." In the appendix to this work, published later, is a 
statement that a certain injurious caterpillar (possibly the 
gypsy moth), in 1721 and 1722, ravaged not only the fruit 
trees throughout Germany, but also oaks and other forest 
trees, and even killed many of them. 

Thomas Brown, in the " Book of Butterflies," Vol. II, page 
52, published in London in 1832, states that in 1731 the 
caterpillars of the gypsy moth committed terrible havoc 
among the cork oaks of France. 

In 1761, J. C. Schaefler published a work on the gypsy 
moth, the first edition of which appeared in 1752. He states 
that in this last year the trees in the orchards and gardens, 
the bushes in the fields, and even whole forests, not only in 
many places in Saxony but also in Altenburg, Leitz, Nauin- 
burg, Sangerhausen and many other regions, were entirely 
stripped of their leaves. The branches and twigs were 
densely covered with caterpillars, instead of leaves, and they 
also crawled over the ground in great numbers. An exam- 
ination proved that they all belonged to this one species, and 



INJURIES IN THE OH) WORLD. 275 

that they had been more or less abundant for three years in 
succession. The first year there were not very many, the 
second they were comparatively numerous and the third year 
they were present in overwhelming numbers. Some of the 
common people thought that the caterpillars grew out of the 
ground, like the grass ; others thought that they were cre- 
ated by the evil one ; still others assured the author that they 
had seen with their own eyes thousands of the caterpillars 
brought by the wind ; and, finally, there were many who 
thought these caterpillars were sent by God as a punishment 
for their sins. The author states that about eleven years be- 
fore, he saw this same species in Saxony, after having stripped 
the leaves from every tree and shrub in the vicinity, feed on 
grass and grain. 

In the " Naturforscher," Vol. XVI, page 130, 1781, Pas- 
tor C. J. Rimrod gave a long and very good account of the 
gypsy moth, and wrote of two invasions at his home in Quen- 
stedt, one in 1760-61 and the other in 1781. 

Preyssler, as stated by Bechstein, in his " Vollstandige 
Naturgeschichte der schadlichen Forstinsekten," page 372, 
1804, says that the gypsy moth was once very common at 
Prague, and stripped the leaves from the fruit trees, so that 
they bore no fruit. Bechstein, in the same place, says that 
this is a formidable insect, against which very active meas- 
ures must be taken, for, because of its large brood and great 
voracity, the damage done by the caterpillars may be easily 
understood. Linnaeus and Fabricius call it the pest of the 
fruit garden. 

Panzer, in his " Faunae Insectorum Germanic*," Vol. II, 
page 22, 1794, says the caterpillars of this insect appeared for 
many years in frightful numbers, and destroyed the fruit trees 
to the great injury of their owners. In 1818, the cork-oak 
forests extending from Barbaste to Podenas, in south-western 
France, were devastated by innumerable hosts of gypsy moth 
caterpillars. After having devoured both the leaves and the 
acorns, they attacked the maize, millet, fodder and all the 
fruits. They even invaded the dwellings in the neighborhood 
of the trees, to the extreme annoyance of the occupants. 

Godart says, in his " Iconographie des Chenilles, Les Bom- 
by cites," published in 1832 : " This caterpillar lives on nearly 



276 THE GYPSY MOTH. 

every species of tree, and, as it is as common as voracious, 
it often causes great damage to orchards of fruit trees as well 
as in the parks and forests, and, together with other cater- 
pillars, often completely defoliates them." This same author, 
in his "Histoire Naturelle," Vol. IV, page 256, states that in 
1823 the trees in the forest of Senart in Fontainebleau were 
entirely defoliated by the gypsy moth, so that the trees were 
as bare as in winter. Finding nothing further to devour, 
the caterpillars crawled over the ground in all directions, 
seeking food. M. Daudeville, writing in the "Annales de 
la Societe d'Horticulture de Paris," Vol. Ill, page 98, 1828, 
after referring to this caterpillar and the descriptions that 
had been given of it, said that the pest extended from the 
west to the north-east of the city of Saint Quentin, for a 
distance of more than sixty miles, and had completely dev- 
astated the trees, so that they were entirely bare. These 
insatiable insects not only devoured the buds, leaves and 
flowers, but even the small twigs of fruit trees. For three 
years, in an orchard of three hundred apple trees, they had 
not left a leaf intact, and the gradual decay and death of 
several of the trees were attributed to these insects. In the 
same journal it was stated that Viscount Hericart of Thury, 
in a journey which he had just completed, observed that the 
apple trees in the departments of Calvados, the Eure, Eure- 
et-Loir, the Seine-Inferieur, Seine-et-Oise, the Oise, the 
Somme and the Aisne were entirely ravaged by this insect. 
Mons. N. Joly, in the " Eevue Zoologique," Vol. V, page 
115, 1842, says that during the years 1837, 1838 and 1839, 
there appeared in the forests around Toulouse in France an 
innumerable quantity of the gypsy moth. The caterpillars 
of this insect attacked the oaks with such avidity as to 
strip them completely of their foliage, so that after the first 
onslaught the trees appeared as they do in winter. The 
caterpillars were so numerous that persons passing through 
the woods could hear them eating, and might easily believe 
themselves in the midst of a menagerie. These devastating 
insects occupied an area of more than twenty-five square 
leagues.* On their approach to Toulouse they attacked 

* An area nearly as large as the infested territory in Massachusetts. 



INJURIES IN THE OLD WORLD. 277 

the willows, which they damaged much less, because of the 
ability this tree possesses of putting on new foliage. In 
the " Stettiner Entomologische Zeitung," Vol. IX, page 266, 
1848, it is stated that Riegel in 1838 saw about eight acres 
of oak woods entirely stripped of leaves by the gypsy moth. 
Ratzeburg, in "Die Waldverderbniss," published in 1868, 
Vol. II, page 154, says the gypsy moth, ten years before, 
had spread, in a space of three years, from Brandenburg to 
the zoological gardens. On page 189 he says that the size 
and voracity of this caterpillar (gypsy moth) and the vast 
numbers in which they sometimes appear make the results 
for the beech, as well as for the elm, frightful in the extreme. 
In the zoological gardens at Berlin the beeches are said to 
have been severely attacked. A very competent observer, 
Dr. Gerstacker, as an eye-witness, stated that in 1852 many 
beeches became dry and dead. In that year all the cater- 
pillars transformed, but in 1853, not having sufficient food, 
many died of starvation. On page 339, in speaking of the 
ravages of different species of caterpillars, he says that 
Bombyx dispar (the gypsy moth) may be mentioned first as 
being the largest and most ravenous, and further says that 
he knew of a devastation by which was caused the weakening 
and death of rnany trees. This author states (page 185) that 
in the great devastation which occurred in the zoological 
gardens at Berlin, in 1851-53, these caterpillars attacked 
not only the native but also the foreign trees and shrubs 
cultivated there, no species being entirely avoided by them. 

Bazin, in an article on "The Ravages upon the Oaks by 
Bombyx dispar" published in "Bulletin de la Societe des 
Sciences historiques et naturelles de l'Yonne," pages 11-20, 
1870, speaks of the abundance of this species everywhere. 
Before the middle of June, 1868, "there were spots in the 
woods that every day spread like spots of oil on the water, 
where not a leaf remained on the trees or shrubs." The oaks 
were attacked first, and after they had been stripped the 
birches, aspens, elms and even pines and larches were com- 
pletely denuded. In the fields a large number of apple trees 
were defoliated by this caterpillar, and the apples themselves 
were sometimes eaten into to such an extent that they became 
malformed. In the same article M. Bazin states that it was 



278 THE GYPSY MOTH. 

reported that caterpillars of this species had occasioned the 
death of children who had eaten strawberries upon which 
these caterpillars had rested, and that, as a consequence, the 
sale of strawberries had been prohibited in certain regions. 
It did not seem possible that the story of the death of the 
children from this cause could be true, or even that any 
derangement of the digestive system could have occurred. 
To test the statement, M. Bazin put four gypsy moth cater- 
pillars in a wide-mouthed bottle with twelve strawberries 
and a strawberry leaf. At the end of twenty-four hours they 
had eaten a very little of the leaf and also a little of the 
strawberries, but had not eaten them with the avidity that 
they do other kinds of food. They had been in contact with 
the strawberries more completely, however, than they would 
if they had been at liberty, for they had crawled over the 
berries again and again, and, if they had the power to impart 
to them any injurious properties by contact, they must have 
done so under these conditions. M. Bazin then ate four of 
these strawberries, and, a little later, feeling no inconvenience 
from these, ate the remaining eight, without the slightest 
disturbance in the stomach. As the opinion prevailed more 
or less widely that cows and other animals that had eaten 
these caterpillars had been made sick, he caused a dog to 
swallow some of them, but the animal gave no indication of 
inconvenience. 

In reviewing Dr. E. L. Taschenberg's "Entomologie fur 
Gartner," etc., in the " Stettiner Entomologische Zeitung," 
Vol. XXXII, page 167, 1871, Dr. Dohrn, in speaking of 
the gypsy moth, says that from his experience the active 
caterpillars, after escaping from the eggs, can crawl about 
for eight or ten days without food. He states that on May 
3, 1854, he was in Glogau, and noticed gypsy moth cater- 
pillars crawling on his own clothing as well as on that of 
others. Under the roof of the shed, near which they sat, 
thousands of caterpillars which had hatched that day were 
crawling about. They had let themselves down by threads, 
and thus dropped upon the clothes of the people. Threads 
from many more caterpillars had become entangled into long 
chains, which waved in the almost imperceptible breeze, and 
from which hung, so far as he could judge, about a thousand 



INJURIES IN THE OLD WORLD. 279 

caterpillars. In another village he saw, some time later on 
a fine day, caterpillars of this same species swaying on long 
threads from apple trees in an orchard, and which, although 
there was no wind, were directed towards a neighboring 
orchard which the owner had always kept carefully cleared 
of caterpillars and egg-clusters, and who had often com- 
plained of the laziness and ill-will of his neighbor. On the 
highway in Herms village, in Glogau, the same summer, a 
large apple tree was eaten almost bare of leaves, and the fe- 
male moths were laying their eggs on the trunk. Later in the 
season Dohrn states that he saw the tenant carefully scrap- 
ing off the egg-clusters, even from the highest branches, and 
he expected the tree would be quite free from these caterpil- 
lars the next year ; but to his astonishment, in the following 
July, it was full of gypsy moth caterpillars, and eaten bare. 
The tenant said he would do nothing more in future, since 
all his work was of no avail ; but, upon questioning him as 
to whether he had burned the eggs, he replied that such a 
thing had not occurred to him. He had simply trodden all 
the egg-clusters and scrapings into the ground, where they 
had been preserved, and the caterpillars, hatching out the fol- 
lowing year, found their way up into the tree. 

In an article in the " Bullettino della Societa Entomologica 
Italiana," Vol. Ill, page 360, 1871, published in Florence, 
Italy, Apelle Dei has an article on the "Ravages of Insects 
in the Senesian Country," in which he mentions the gypsy 
moth, stating that it had ravaged the oak forests of the high 
Chianti for many years, and during the year 1871 they had 
stripped the forests of Chianti to an extent and with a sever- 
ity that was frightful, and that many of the oaks had been 
destroyed. Dubois, in his " Lepidopteres de Belgique," 
Vol. II, published in Brussels in 1874, states that in 1858, 
Brussels and its neighborhood suffered very much from the 
ravages of the gypsy moth, notably the boulevards and park. 

Porchinsky, in his work on ' ' Insects Injurious to Fruit 
Gardens in the Crimea, Russia," published in St. Petersburg 
in 1889, states that the gypsy moth caterpillar appears in the 
Crimea not unfrequently in enormous quantities. This hap- 
pened in 1842, and also in the early sixties and seventies. 
Especially during 1871 were the gardens of the Crimea nearly 



280 THE GYPSY MOTH. 

destroyed. In 1884 these caterpillars were so numerous that 
they covered the railroad tracks so that trains were moved 
with difficulty. Again, in 1885, they occurred in great num- 
bers along the southern shore. Observations in the Crimea 
show, however, that the gypsy moth rarely continues in the 
same locality in large quantities for more than three years. 
Thus in 1861, an unusually large number of caterpillars was 
noticed in the Crimea, and they continued to increase until 
1863, when their highest number was reached. Although 
the greater part of the caterpillars succeeded in forming 
cocoons, yet very many of them were diseased, as was shown 
by their soft and withered condition, and, when broken open, 
there flowed out from some of them a dark-brown liquid 
mass. In 1864, there were decidedly less caterpillars than 
during the previous year, while only occasional individuals 
were met with in 1865. 

In a work on " Insects Injurious to Gardens and Orchards 
in Central and Northern Russia," by N. Kulagin of the Uni- 
versity of Moscow, published in St. Petersburg in 1894, it 
is stated that the gypsy moth is very widely distributed. It 
is found in all the central provinces of Russia, in the Cauca- 
sus and in southern Siberia. Besides injuring fruit trees, 
the caterpillars destroyed the leaves of forest trees over an 
extent of territory comprising from one thousand to three 
thousand dessatines (2,860 to 8,580 acres). 

In a work on "Injurious Insects," by Theodore Keppen, 
published in Russia in 1883, Vol. Ill, commencing , on page 
49, it is stated, in speaking of the gypsy moth, that these 
caterpillars often appear in countless numbers. In 1852, in 
the vicinity of Kishenev, eighty-three miles north-west of 
Odessa, they occurred by millions in the gardens and forests. 
Having destroyed all the leaves, they attacked the bark 
of the young shoots and completely ruined a large number 
of different kinds of trees. In 1842, and also in the early 
sixties and seventies, Georg Seopru states that they were 
exceedingly injurious to the fruit trees in the Crimea. Ac- 
cording to the statements of Professor Eversmann, the for- 
ests of oak and aspen, in the province of Orenboorg, were 
stripped of their leaves, presenting the same appearance 
as in winter. In 1852, the caterpillars laid waste the forests 



Explanation of Plate 40. 



Drawn in colors by Ella M. Palmer. 



Showing the feeding and spinning habits of gypsy moth cat- 
erpillars of different ages. The bark on the lower part 
of the apple twig has been eaten by the young cater- 
pillars early in the season. 

Showing the method of feeding upon a young growing shoot 
of white pine (Pinus strobus) . 

Red oak {Quercus rubra) leaf attacked by a nearly full- 
grown gypsy moth caterpillar. 



rLATE 40. 







Feed, ng HABITS ofGypsy Mom Caterp, 



U.ARS. 



INJURIES IN THE OLD WORLD. 281 

of oak, linden and beech in the province of Kazan, but sub- 
sequently these trees put out a new set of leaves. 

The late V. E. Graft* reported that the oak suffered greatly 
in the province of Yekaterin. In 1856, the gypsy moth was 
observed in great abundance in the province of Riazan. In 
1857, the forests near the province of Tambov were visited 
by vast masses of these caterpillars. The trunks of the wild 
apple and cherry trees were wrapped about with a felt-like 
substance formed by the covering of the eggs. During 1863, 
these caterpillars were seen in vast numbers on the oak in 
various forests in the province of Kazan. Here, as stated 
by Tideman, the trees injured most were the oak, linden, 
maple, elm and birch, while the mountain-ash and hazel-nut 
did not suffer so much. In 1867, the caterpillars were seen 
in other districts, and in 1868, their numbers became fright- 
ful to contemplate throughout the whole province of Kazan. 
In 1867 to 1869, the gypsy moth caterpillars were very de- 
structive in the province of Samara, and Rudzky states that 
they were very abundant at the same time in all parts of the 
province of Penza. During June, 1867, all the trees on 
many estates were entirely stripped of their leaves, and the 
forests in many cases to the extent of several hundred des- 
satines * appeared as they do in the winter. The caterpillars 
seemed to prefer the oak and linden, but after defoliating 
these they attacked other trees and shrubs, and finally de- 
stroyed the grass. In the forests near the city of Penza the 
dead caterpillars formed such putrid masses that the police 
were obliged to take measures to destroy the decaying heaps. 
An incalculable quantity of eggs were laid on the trunks of 
both deciduous and evergreen trees. In 1869 and 1871, the 
gypsy moth caterpillars appeared in great quantities in the 
Kupiansk district of the province of Kharkov. 

In more recent times, 1879-80, these caterpillars multiplied 
in frightful numbers and spread over an immense territory, 
beginning in the province of Kiev and Poltava and extend- 
ing through Kharkov, Voronezh, Tambov, Saratov, Sim- 
beersk into Kazan, f Owing to defective reports concerning 



* One dessatine is equal to 2.86 acres. 

t A territory about equal to all our Atlantic States, and in nearly the same lati- 
tude as Labrador. 



282 THE GYPSY MOTH. 

this unusual appearance of Porthetria dispar, it is hard to 
say Avhere the calamity began. Considering the time of their 
appearance, it is supposed that they first appeared en masse 
in the province of Kharkov. According to Yaroschev, the 
caterpillars were seen in threatening numbers in the district 
of Zmiev during 1877-78. The insect may have spread 
westward in the province of Poltava and eastward in the 
province of Voronezh, and from these to more distant parts. 
The simultaneous appearance in different places so widely 
separated, led to the opinion that there were various places 
of origin from which the insect was distributed. Yaroschev 
states that the caterpillars were so abundant in the vicinity 
of Zmiev, in 1878, that in going from one forest to another 
they literally covered the walls of the houses lying in the 
way. They fed on all sorts of plants, except ash {Fraxinus 
excelsior') and wild pear. 

Anderson gives interesting details of the presence of the 
caterpillars in the forest of Shipov in the province of Voro- 
nezh. They first attacked the so-called winter oaks ( Quer- 
cus pedunculated, var. tardiflora), and, after destro} 7 ing the 
leaves as soon as they appeared, they devoured the leaves of 
the lime tree, aspen, hawthorn, spindle tree, hazel and others, 
and finally the numerous grasses were destroyed. Early in 
June they began to pupate, and by the middle of the month 
they were all in this stage. About 3,500 dessatines (10,010 
acres) of the forest were laid bare, and detached trees in 
other parts of the woods were stripped of their leaves. By 
the middle of July the moths had emerged and laid an enor- 
mous number of eggs. 

According to Gazen, vast quantities of these caterpillars 
were seen in the district of Kirsanov in the province of Tam- 
bov, in April, 1879. Having eaten all the leaves on the trees 
and shrubs, the caterpillars descended to the ground and lit- 
erally covered it in all directions. In the district of Volsk, 
in the province of Saratov, the caterpillars of the gypsy moth 
appeared in vast numbers in April, 1879, eating the leaves 
of all sorts of trees, though preferring. the birch and oak, 
and finally they attacked the pine. By the end of May, 
10,000 dessatines (28,600 acres) of forest were completely 
denuded of their leaves. After this they devoured the 



INJURIES IN THE OLD WORLD. 283 

grass, and, coining to a field of grain in their march, they 
destroyed that also. In 1880, they appeared in force in the 
forests of the provinces of Simbeersk and Kazan. 

In a letter from Professor Henry of the School of For- 
estry, Nancy, France, dated July 27, 1895, he says : "Liparzs 
dispar (the gypsy moth) is well known to French foresters. 
This caterpillar is a plague to fruit trees, oaks, chestnuts, 
lindens, elms, poplars and other trees, on all of which it 
thrives. In 1868, more than 60 hectares (148| acres) of oak 
woods were entirely stripped by it. It was so common in 
1880, on the sides of Mt. Ventoux near Avignon, that the 
legions of caterpillars covered the ground and entirely de- 
stroyed vegetation. In Savoy it made an invasion in 1887 
upon the chestnuts and fruit trees. There is not a year 
passes, comparatively speaking, in which the caterpillars do 
not show themselves in our territory, if not in one place 
then in another." In a letter from Dr. J. Ritzema-Boz, from 
Amsterdam, Sept. 3, 1895, he writes that this insect is com- 
mon in Holland and also in all western Europe, but the 
ravages of the caterpillar are very much more common in 
the eastern parts of Europe. In Holland the ravages of the 
gypsy moth are very rare indeed. In 1848, it stripped the 
leaves from the oak (Quercus pedunculated) over 50 hectares 
(123 T 7 g acres) near Lutphen in the Dutch province of Gelder- 
land, and then attacked the other trees. In 1887 it was very 
abundant on oak near Wyrnegen in the province of Gelder- 
land. In 1880 these caterpillars destroyed the leaves on a 
large number of hectares of oaks near Veenendeal in the 
province of Utrecht. 

In a letter from N. Nasonov, of the University Museum of 
Zoology, in Warsaw, Poland, dated Aug. 7, 1895, he writes 
that he had the opportunity of knowing personally of an 
immense number of the caterpillars of the gypsy moth in 
the orchards of the government of Warsaw during the years 
1891 and 1892, and also on the deciduous trees in the 
government of Moscow in 1894. In 1892, the leaves of 
the fruit trees in Warsaw were eaten by these caterpillars 
to such an extent that they bore no fruit. According to 
the information received from the central Russian govern- 
ment, the caterpillars of the gypsy moth have this summer 



284 THE GYPSY MOTH. 

(1895) nearly defoliated the forests in the government of 
Kalonga. 

Notwithstanding the general damage to all kinds of vege- 
tation in Europe, the greatest complaint comes from the 
fruit-growing districts, where this insect shows a preference 
for the foliage of fruit trees. 



Methods of Destroying the Gypsy Moth in Europe. 

The natural enemies of the gypsy moth, as the birds, 
parasites and predaceous insects, are relied upon to a great 
extent to keep it in check in European countries, except in 
localities where it is very abundant, and the outbreaks very 
frequent. It should be borne in mind that the European 
methods are not for the purpose of exterminating or even 
preventing the spread of this insect; for, as has already 
been stated, it is more or less common everywhere. The 
extermination of this pest in Europe by artificial means 
would probably be an absolute impossibility, and, therefore, 
all that is attempted is to destroy it wherever it appears in 
great abundance. 

The usual methods are to scrape otf the egg-clusters and 
burn them, or cover them over with raupenleim or other 
materials in the fall, winter or spring before they hatch, 
applying the substance by means of a brush on a long 
pole to those egg-clusters that are too far above the ground 
to be reached in any other way. Later in the season the 
trees are protected from those caterpillars that hatch from 
egg-clusters laid on the ground or elsewhere, by banding 
with raupenleim. The caterpillars are destroyed whenever 
found, generally by crushing them as soon as they hatch, 
and while they are still clustering on the egg-mass, form- 
ing the so-called " spiegel." The pupae are destroyed by 
hand, and also the female moths before they have laid their 
eggs. 

Dr. N. Nasonov, of the Warsaw University Museum of 
Zoology, in the letter previously cited, writes that, in Po- 
land, the principal measures used in combating these in- 
sects are to destroy the eggs, band the trunk of the trees 
with raupenleim and gather the caterpillars and pupae by 



REMEDIES IN EUROPE. 285 

hand. In a Russian work * by A. F. Rudzky, is given the 
following : "The eggs are laid on the trunks of the trees in 
large masses. These may be easily scraped off with a knife 
during ten entire months in southern Russia. If the egg- 
clusters are not scraped off, it is necessary to destroy the 
caterpillars as soon as hatched, and while still clustering in 
groups. When the caterpillars have spread over the whole 
tree, it is as impossible to destroy them as the separate 
moths. When they have eaten the foliage from one tree, 
they go in a mass to another ; but this may be, in a measure, 
prevented by putting the so-called ' catch bands ' on the tree 
trunks. The cheapest of these bands are made of wadding, 
five or six inches in width, and bound on tightly, leaving an 
upper and lower edge, which is to be roughed up, so that 
the caterpillars may become entangled in the uneven sur- 
faces. The wadding may be made fast to the trunks with 
strings, or glued together in bands. Where a large number 
of these bands are needed, it is advisable to paste the wad- 
ding (during the winter) on coarse paper, one side of which 
is smeared with tar. Bands of pitch or tar are frequently 
used, but these soon become dry. In the Crimea, a mixture 
of two parts of boiled tar and one part of rape oil, thoroughly 
heated together, is used ; also a mixture of ten pounds of 
lard, twenty pounds of hemp-seed oil and eighty pounds 
of coal tar. This is applied directly to the tree and needs 
renewing twice a year. Labodsky recommends this same 
ointment, and says that, when well prepared, it will retain 
its sticky qualities an entire autumn." 

Theodore Beling, inspector of forests at Seesen, wrote 
July 21, 1895, that the methods adopted there were to kill 
the caterpillars, pupae and moths, but that the most impor- 
tant method was to destroy the egg-masses on the tree trunks 
by scraping them off and burning them, or by covering them 
with raupenleim, or with a mixture of four parts of wood 
tar and one part of petroleum. Dr. Richard Hess, in "Der 
Forstschutz," published in Leipzig, 1887 and 1890, gives 
the following concerning the gypsy moth: "Prevention: 
Protection of its enemies, bats, cuckoos, starlings, crows, 

* " Insects Useful and Injurious to Fruit Trees." 



286 THE GYPSY MOTH. 

titmice, tree-creepers, etc., ichneumons and tachinids are 
especially to be noted. Orchard trees should be smeared 
with a thin mixture of lime, black-soap, potash and cow- 
dung. Killing: Destruction of the egg-masses, from August 
to April, by scraping them off and burning them, or by 
smearing them with wood-tar thinned with petroleum or 
raupenleim. Killing the * spiegel' in May, and crushing the 
caterpillars when clustering on the trunks and branches of 
the trees, from the end of May through June ; gathering the 
pupae in July and August." In a letter from Dr. Ebermayer, 
professor in the University of Munich, dated July 22, 1895, 
substantially the same methods are recommended. 

J. Porchinsky, in his work on "Insects Injurious to Fruit 
Gardens in the Crimea," says: "The eggs should be de- 
stroyed in the winter season, when time and circumstances 
permit. The egg-clusters should not be crushed, as this 
might allow some of them to escape ; but they should be 
carefully scraped off and burned. The eggs having been 
destroyed, the tree should be protected from caterpillars that 
might come from neighboring trees by 'catch bands' (pre- 
ventive bands). These preventive bands are almost the only 
means with which to combat insects of all classes most injuri- 
ous to orchards ; and, therefore, their consideration is of the 
first importance ; but it is not so easy to find a paste that 
will, under all conditions of weather, retain the peculiar 
qualities desired. The most simple of these ' catch bands ' 
is a belt of tar put around the trunk of the trees, on thick 
paper, smeared with tar and made fast to the trunks. 

"In the Crimea, axle grease is placed about the tree 
trunks in belts from three and a half to seven inches in 
width, and about twenty-eight inches above the level of the 
ground. This ointment often retains its sticky qualities a 
long time, yet it is far from satisfactory. 

" The experiments of Klausen, in which he used wadding 
as a catch band, are of importance in connection with the 
question of prevention. A large number of these bands of 
cotton were put around the trunks of trees, the upper and 
lower borders being well spread out, for, the more fluffy and 
open the cotton, the more easily the caterpillars become 
entangled. In the course of two hours a large number of 



REMEDIES IN EUROPE. 287 

caterpillars became entangled, and by evening were dead. 
After a rain these bands should be replaced." 

By the advice of Prof. B. E. Fernovv, of the Department 
of Agriculture, Washington, D. C, I wrote the following 
letter to Professor Altum : — 

Amherst, Mass., U. S. A., Jan. 21, 1895. 
Prof. Dr. Bernard Altum. 

Dear Sir : — I send you by post some papers which contain an 
account of the introduction and spread of the " Schwammspinner" 
(Ocneria disjoar L.) in this country, and of the efforts that have 
been made to exterminate this insect. You will see by an exam- 
ination of these papers that the insect has proved more destructive 
here than it usually does in Europe, while in England it has be- 
come extinct from unknown natural causes. 

We have already found several parasitic and predaceous insects 
preying on 0. dispar, as you will see mentioned in the reports 
which I send to you ; but I very much wish to learn whether you 
think it would be wise for us to attempt to introduce the European 
parasites into this country ; and, if so, what parasites would it be 
desirable for us to introduce, and where and how can they be best 
obtained ? We have been advised to introduce some of the Euro- 
pean predaceous beetles, as Calosoma sycojihanta (L.), Calosoma 
inquisitor (L.) and Silplia quadripunctata L. Others have told 
us that Calosoma sycophanta is so large and conspicuous that 
insectivorous birds would destroy it to such an extent that it would 
prove of little assistance in destroying the '* Schwammspinner." 
Will you be so kind as to give me your advice on this subject, and 
also any information you may have of the methods used in Europe 
for the destruction of this insect? I have your valuable work on 
" Forstzoologie," but from all I can learn this insect is more 
troublesome and destructive in southern Europe than in Germany. 
I shall be very grateful for any information that you may be able 
to give me. 

Very respectfully, your obedient servant, 

C. H. Fernald. 

In reply to the above letter Professor Altum wrote as 
follows : — 

I have never known of a devastation in Germany equal in severity 
and extent to that in your country. So far as I know, all of the 
devastations of dispar in this region have occurred on limited 
areas, and have always quickly disappeared. 



288 THE GYPSY MOTH. 

An importation of predaceous insects to oppose this destructive 
dispar, e. g., Calosoma sycophanta, etc., cannot possibly be of 
any industrial importance. These work in no noteworthy degree 
even in our far smaller dispar calamities. There are small para- 
sitic insects, especially the species of Microgaster, and even mi- 
crobes (bacteria), which are valuable. But these can only be 
collected and sent away when they appear in multitudes, and I do 
not know at present of a single case in which there is such an 
appearance. 

I can only recommend a single successful artificial remedy, 
namely, painting or moistening the egg-clusters with liquid fat 
(oil, petroleum, train oil) or with thin liquid wagon grease, raupen- 
leim, etc. With brushes having long handles, and also by the use 
of ladders, most of the egg-clusters can be reached. As a rule, 
these egg-clusters stand out visibly from the darker green bark of 
the trunks and branches, the under side of which may be cleaned 
with a brush attached to a pole. This work can be done from 
September to April, and has always been a complete success here ; 
but with such an enormous and extensive development as dispiar 
presents with you, the successful execution of the above method 
of destruction does not seem possible ; moreover, no other artificial 
method is of value. You will, therefore, for the present, make 
use of this method where the insect appears in small numbers, or 
as single individuals beyond the area being destroyed, and also 
where the first colonies or gathering points appear, that is to say, 
where a great development of the insect is feared. Here the in- 
sects are in such numbers that it is possible to destroy them, and 
are, for the most part, to be found on the lower portion of the 
trunks of the trees, where they can be easily reached by the hand 
or with short-handled brushes. These later central points of the 
invasion usually have a small area and definite borders, and such 
a method of destruction must be adopted and carried on with all 
possible energy, for the protection of the surrounding territory. 
It is needless to say that the caterpillars, pupae and female moths 
should be destroyed. 

The Eggs. 

The eggs (Plate I, Figs. 9 and 10) are nearly globular, 
slightly flattened on the lower side, and generally flattened 
or depressed on the upper side. They are about one-twen- 
tieth of an inch (1.5 mm.) in lateral diameter, and of a dark 
salmon color when first laid ; but when fertile they change 
to a darker color, owing to the development of the embryo, 
which is quite fully formed in about three weeks. The egg 




PLATE 41. Mass of pupa-cases and egg-clusters under a fence rail. 



THE EGGS. 289 

appears to be smooth, when examined with a lens, but if the 
shell be very carefully removed and examined under a half- 
inch objective, or a higher power, it exhibits somewhat 
irregular hexagonal marks over the entire surface, except at 
the centre of the depression above, which is occupied by the 
micropyle with its surrounding rosette. This consists of 
three rows of somewhat pear-shaped cells, each row over- 
lapping a part of the next outside of it (Plate 58, Figs. 
11 and 12). The most successful method found for ren- 
dering the micropyle and surface markings visible was to 
remove the contents of the egg and mount the shell dry. 
When mounted in Canada balsam, glycerine or glycerine 
jelly, all the markings were obliterated. It was impossible 
to obtain any better, or even as good, results by first stain- 
ing the shells in hematoxylin, eosin, aniline red, aniline 
blue, picro-carmine or methyl green. This last stain, how- 
ever, gave better results than any of the others. 

The eggs are laid in the summer, soon after the emergence 
of the moths, in oval or rounded clusters (Plate I, Fig. 8), 
usually containing from four hundred to five hundred eggs, 
but clusters have been found which contained one thousand 
eggs. These egg-clusters vary in size from one-half an inch 
to one and one-half inches in length, and from one-third of 
an inch to one inch in width. The average dimensions of 
fifteen clusters were found to be 21 if mm. long, 11 1 mm. 
wide and 5£ mm. deep. The female covers the eggs, as 
she deposits them, with the yellowish hairs from the under 
side and end of the abdomen, which cause the cluster to re- 
semble a small piece of sponge in general appearance (Plate 
I, Fig. 8). In time, however, they fade, and more nearly 
resemble the eggs of the white marked tussock moth (Plate 
39, Fig. 15). The female deposits her eggs in every con- 
ceivable place, as on the branches and trunks of trees (Plate 
55), often below the surface of the ground when this has 
shrunken away from the tree ; in cavities in trees or other 
concealed places ; under bark which has separated from dead 
branches ; under bands of tarred paper or cards tacked upon 
the trees ; in stone walls ; under stones and in cavities in the 
ground ; in old tin cans, on dead leaves or other rubbish 
near the infested trees; under fence rails (Plate 41) or the 



290 THE GYPSY MOTH. 

loose boards or timbers of barns or out-buildings ; in birds' 
nests, and many other places, occasionally on leaves on the 
tree and sometimes on the fruit ; but undoubtedly the trunks 
and branches of the trees (Plate 42) are the most natural 
places. As a rule, the eggs on the limbs are laid on the 
under side, although in a few instances they have been found 
on the upper side, but more or less concealed. In one case 
an egg-cluster was found on a piece of old rope hanging from 
a tree, and another on a thermometer hanging against the 
outside of a chimney. It is not an uncommon thing to find 
them in tent caterpillars' nests, and one was found deposited 
on a spider's web on a fence. 

The typical form of an egg-cluster is elongated and slightly 
narrowed at the end last laid. This form is subject to all 
imaginable variations, according to the conditions under 
which the mass of eggs is laid. In one instance, six appar- 
ently complete egg-clusters were observed that had been laid 
nearly on top of each other ; and in another, a female that 
appeared to have died on her egg-cluster was nearly half 
covered with eggs deposited by a second moth while laying 
close by. Eggs laid by unfertilized females are usually 
poorly covered with hair, and crippled females, as well as 
those which have trouble about emerging, often leave a large 
part of the hair of the abdomen in the pupal case. Eggs 
laid by such females are usually stuck together in a loose 
mass, poorly covered and easily separated. The adhesive 
substance by which the eggs are attached to each other and 
to the surface upon which they are deposited, as well as that 
which causes the hairs of the abdomen to adhere to them, is 
insoluble in dilute or absolute alcohol, chloroform or spirits 
of turpentine. 

Scattered Eggs. 

In nearly every case where a fertilized female was confined 
in a box, she was found to scatter eggs while laying. The 
eggs were dropped accidentally, the moth being unable to 
attach them to the surface on which she rested. Frequently 
a considerable number were dropped before she succeeded in 
attaching a single egg ; but after a small number had been 
securely deposited, fewer eggs were scattered, although occa- 
sionally they were dropped throughout the entire process of 




PLATE 42. Mass of egg-clusters on the trunk of a large elm. 



SCATTERED EGGS. 291 

laying. The most marked eases of egg-seattering were those 
where the moth did not first form a hairy area on which to 
deposit eggs. Observations made on the egg-scattering of 
fifteen gypsy moths, ten in the insectary and five on trunks 
of trees in the field, showed that all of them scattered eggs, 
some of which were dropped before the moth mated and 
others afterwards. The number of eggs scattered by these 
insects ranged from one to thirty-four, the average being 
nine and three-fourths. Male moths, when numerous, in 
attempting to mate with females while they are laying, often 
disturb them to such an extent as to cause them to drop or 
scatter eijffs. JLgvs scattered by fertilized females have 
proved to be fertile. Observations made in the field show 
that many eggs are scattered by the moths when laying 
under the most natural conditions. In one colony in Sau- 
gus, in 1894, the greatest number of egg-clusters were on 
the rough bark of pine trees, and many scattered eggs were 
found at the base of these trees among the pine needles. 
Nearly all of these eggs were naked, and in many cases the}' 
were loose, though some were attached to pine needles or to 
fragments of bark at the base of the trees. Scattered eggs 
were also found in crevices of the rough bark below the 
clusters. Eighty-five per cent, of the scattered eggs taken 
at this place proved to be fertile. This scattering of eggs 
doubtless explains why caterpillars occur in places where 
the eggs on the trees have been destroyed the previous 
winter, and indicates the value of burlapping as a supple- 
ment to the work of egg destruction. 

Resistance or Eggs of the Gypsy Moth to the Action 
of the Elements. 
In January, 1895, a number of egg-clusters were thor- 
oughly broken up, so that the eggs were entirely separated, 
and as much of the hair removed as possible. The eggs 
from each cluster were then placed in a small paper box 
which was covered with two thicknesses of thin, open cheese- 
cloth. Six of the clusters were placed underneath the store- 
house, where they were sheltered from storms, but otherwise 
wholly exposed to all climatic changes ; and, to determine 
the effect of the actual out-door exposure, six more egg- 



292 THE GYPSY MOTH. 

clusters were taken from trees, and, after being prepared in 
the same manner, were placed in exposed positions on the 
ground, in the centre of a colony. The tops of the boxes 
were placed uppermost, so as to give free access to rains, 
and the localities marked, so that they might be readily found. 
The boxes were allowed to remain here through all the cold 
weather and storms of the season, sometimes being bare, and 
sometimes covered by the ice formed from the melting snow. 

On the 4th of April, all of these egg-clusters, as well as 
those from underneath the storehouse, were collected and 
placed in the hatching-boxes. Those from the colony were 
more or less covered with cUbris which had been carried into 
the box by the action of rain or of thawing ice. All of the 
egg-clusters hatched from April 16 to April 20, and, judging 
from the small number of eggs remaining unhatched, pro- 
duced as many caterpillars as similar clusters which had been 
kept intact, either in cold storage or out of doors, during 
the winter. 

From this it is evident that, although the hairy covering 
of the egg-cluster may serve in a measure as a protection to 
the eggs, yet it is not essential to their successful hiber- 
nation. Certain European writers recommend scraping the 
eo-o-s from the trees, and state that when this is done their 
vitality is destroyed by the severity of winter. This cer- 
tainly is not true in Massachusetts, even if it be so in 
Europe. 

Effect of Extremes of Temperature on the Eggs of 
the Gypsy Moth. 

During the spring of 1895, considerable time was devoted 
to studying the effect of heat and cold, in extreme degrees, 
upon the eggs of the gypsy moth, with a view of obtaining 
a better knowledge of the capabilities of this insect to resist 
such extremes, which fact has a bearing in showing whether 
sudden climatic changes would aid in holding the insect in 
check. 

The experiments with extremes of heat were conducted by 
use of a hot- water oven, the necessary degree of heat being 
obtained by means of a small oil stove, and the temperature 
of the interior being indicated by a small thermometer. 



EXPERIMENTS ON EGGS. 293 

To obtain extremes of cold, the eggs were placed in vials 
and enclosed in a small can, which -was then placed in an- 
other can containing a freezing mixture (composed of equal 
parts of coarse granulated snow and salt, and in some cases 
one which was composed of four parts of snow and five parts 
of calcium chloride). The degree of cold was indicated by 
a thermometer placed in the freezing mixture, and so ar- 
ranged as to be easily read through a glass window in the 
side of the can. 

Effect of Heat on Eggs. 

On April 3, ten egg-clusters of the gypsy moth were ex- 
posed for thirty minutes to a temperature of 80° F. They 
were then placed in the hatching-boxes, where the temper- 
ature was normal, and daily observations made until April 
16, when all the egg-clusters were found to have hatched. 
April 3, ten egg-clusters were exposed for thirty minutes 
to a temperature of 90°, and were then placed in hatching- 
boxes ; all of the clusters had hatched April 16. April 
3, ten egg-clusters were exposed for thirty minutes to a 
temperature of 100°, and then placed in hatching-boxes ; by 
April 17, all had hatched. April 3, ten egg-clusters were 
exposed for thirty minutes to a temperature of 110°, and 
then placed in hatching-boxes ; on the 17th of April all of 
these egg-clusters had hatched. March 26, three egg-clusters 
were exposed for thirty minutes to a temperature of 120°, 
and then placed in hatching-boxes ; one of these hatched 
April 7 and the other two on April 9. On April 3, ten egg- 
clusters were exposed for thirty minutes to a temperature of 
130°, and then placed in hatching-boxes; on April 12, all 
of these egg-clusters commenced hatching. Having obtained 
this result, they were further experimented with by being 
placed in a cold box surrounded by ice and salt, and ex- 
posed for thirty minutes to a temperature ranging from zero 
to 8° below ; none of the egg-clusters hatched after this 
treatment. April 15, ten egg-clusters were exposed for a 
period of fifteen minutes to a temperature of 140° ; none 
hatched. April 16, six egg-clusters were exposed to a tem- 
perature of 150° for a period of fifteen minutes, and then 
placed in the hatching-boxes ; none hatched. 



294 THE GYPSY MOTH. 

From the above experiments we conclude that a temper- 
ature of at least 140° is necessary to destroy the vitality of 
the developed embryo in the egg. In March, 1895, the 
effect of the naphtha torch flame was tried upon egg-clus- 
ters, exposing them to the action of the flame for various 
short periods of time. This apparatus is sometimes used for 
destroying eggs laid in cavities in trees. Of thirty-one egg- 
clusters treated in this manner none hatched. 

Effect of Cold on Eggs. 
Experiments in rapidly changing egg-clusters from a high 
to a low temperature were conducted with the following re- 
sults : March 22, 1895, four egg-clusters were changed in 
twenty minutes from a temperature of 80° above zero to 5° 
above, and left over night in a freezing mixture of calcium 
chloride and snow. Two of the egg-clusters hatched April 9 
and two April 11. Apparently these egg-clusters hatched 
as well as the average ones in the field, and the caterpillars 
from them fed and grew in as satisfactory a manner as 
normal caterpillars. March 26, two egg-clusters were ex- 
posed for some time to a temperature of 80° F. They were 
then packed in a mixture of calcium chloride and snow, and 
in fifteen minutes reduced to a temperature of 20° below 
zero, a fall of 100°. They were kept at this temperature for 
thirty minutes, and then taken out and placed in the hatch- 
ing-box. By the 16th of April all had hatched. 

Date of Hatching. 

The eggs of the gypsy moth hatch in the spring, from the 
last of April to the middle of June, depending on the weather 
and the places in which they are deposited, those eggs which 
are laid in warm, sunny places hatching the earliest, while 
those that are laid in cold places, being protected from the 
heat of the sun, hatch much later. The earliest recorded 
date of hatching in the field was April 1, 1892, in Medford, 
and on May 14 of the same year a large part of the eggs in 
warm, sunny places had hatched. The latest date noted was 
June 17. 

The embryo develops very rapidly, especially in a warm 
temperature. Eggs laid Aug. 10, 1894, showed well-de- 



SECOND BROOD. 295 

veloped embryos August 26, and eggs were found in the 
field, Aug. 18, 1894, that contained mature embryos 1.4 mm. 
long. Notwithstanding this early development of the em- 
bryo, up to this year no eggs were found to have hatched 
in the fall, though a careful watch was kept for them. In 
Europe fall hatching is reported in at least one instance. 
Ratzeburg, in " Die Forst-Insecten," Vol. II, page 112, says : 
" Here they remain [on the branches] much like a long mass 
of fungus until the next April or May, or by exception they 
hatch in the autumn, as I have seen them myself on the 
5th of September, 1836." 

A Second Brood. 

In the early part of September, 1895, many of the gypsy 
moth egg-clusters were found to be hatching at the ' ' Win- 
ning" colony, in Woburn, where the caterpillars had com- 
mitted serious depredations during the summer months. 
The second brood, which appeared only in this particular 
colony, seemed to have hatched because of peculiar condi- 
tions of location and temperature. The colony is situated 
on the side of a hill, sloping towards the south, which is 
covered with a dense growth of medium-sized oak trees. 
When this colony was discovered, in the early part of the 
summer, the caterpillars were much larger and more nearly 
ready to pupate than in any other colony, and this led to the 
opinion that the eggs must have hatched much earlier than 
in other localities. Many of the moths emerged and laid 
their eggs at this place before the caterpillars in other colo- 
nies, where the conditions for rapid development were not 
as favorable, had commenced to pupate. 

While embryonic development in this insect appears to be 
more rapid in warm weather, a limited number of experi- 
ments performed in 1893 and 1894, seem to indicate that a 
certain degree of cold is probably necessary to mature the 
embryo. In the latter part of August on several nights the 
temperature fell quite low in the eastern part of the State, 
and on one night a frost occurred in some places. At this 
time a part of the eggs in the " Winning"' colony had been 
deposited from four to six weeks, which was sufficient time 
for the development of the embryo. This cool weather was 



296 THE GYPSY MOTH. 

followed by a hot wave, during which a thermometer, ex- 
posed to the direct rays of the sun at Maiden, reached a 
temperature of 112° F. This extremely hot weather caused 
a part of the eggs in this colony to hatch, thus giving rise to 
a second brood, although in no case was the hatching com- 
plete, as only a few eggs (one to twenty-five) hatched from 
a cluster. Eggs brought to the insectary, and kept at an 
average temperature of 70°, gave rise to a few caterpillars, 
from time to time, for more than a month. 

A number of the caterpillars from this second brood were 
collected and sacked in on a small red oak tree, and others 
were taken to the insectary and fed daily. At the time of 
this writing (Dec. 5, 1895) a part of the latter have pupated. 
Careful observations were made upon the caterpillars sacked 
in on the tree, and also upon those which were feeding under 
natural conditions in the colony. In neither case were they 
found to thrive in a normal manner, and with cooler weather 
and frosty nights they gradually died, until none were left. 
Those which survived longest had nearly all entered the 
second molt. The caterpillars reared at the insectary did 
not show as much strength and vigor as those which hatched 
normally in the spring, and over seventy-five per cent, of 
them died before reaching the fifth molt. 

While this is the only positive record of a second brood 
of the gypsy moth in this country, it is presumably true that 
in some cases egg-clusters may have partly hatched in the 
fall of previous years. Any egg-cluster taken in the field, 
which possesses marked peculiarities, is usually sent to the 
insectary for examination, and many of the clusters thus sent 
in during the winter and spring ol 1894-95, were found to 
contain empty egg-shells. The size and appearance of the 
holes in the shells indicated that it was not the work of mites, 
since they eat out a ragged, irregular opening, while the hole 
left by the exit of the young caterpillar has a more regular 
outline, and varies from a small circular aperture to a nar- 
row band eaten around the entire periphery of the shell. 
After studying a number of these egg-clusters during the 
spring of the present year, Mr. Kirkland suggested that 
fall hatching would best explain the occurrence of the empty 
egg-shells ; but at that time there was no positive evidence 



HATCHING OF THE EGGS. 297 

that such hatching had actually taken place in the infested 
district. In the light of our present knowledge, however, 
it seems probable that fall hatching may have occurred occa- 
sionally during previous years, and also that, under the most 
favorable conditions, this insect shows a tendency to be- 
come double-brooded, like the related species of the genus 
Orgyia. 

The death of the caterpillars of the second brood, feeding 
in the field, was to be expected, since the season was not long 
enough to permit them to reach maturity. Even if they had 
matured it is doubtful if the caterpillars would have seriously 
injured trees which had retained their foliage throughout the 
summer. 

On the softer and more delicate foliage of those trees 
which had leaved out a second time, after being stripped 
early in the season, the caterpillars fed with great avidity, 
and, had the length of the season permitted, such trees might 
have been injured to a considerable degree. 

Hatching of the Eggs. 

The majority of the eggs hatch during the warm part of 
the day, from 10 a.m. to 2 p.m., and continue hatching for 
several days. It is apparent that, when hatching, the cater- 
pillar first eats a hole through the side of the egg-shell, the 
flattened surfaces representing the top and bottom of the 
egg, and then eats more or less of a band around the shell 
on the side, often leaving only the upper and lower surfaces 
of the egg. Sometimes the caterpillar emerges from the 
egg by a single hole in the side, but usually it eats a band 
around the side of the egg, leaving only the upper and lower 
disks remaining. 

Number of Caterpillars from Single Egg-clusters, 
and Time required for Hatching. 

From one egg-cluster that had been kept in a warm room at 
the insectary during the winter of 1893-94, 1 egg had hatched 
Feb. 23, 1894, at 9 a.m. ; at 10 a.m., 49 more; at 11 a.m., 
13 more ; and at 5 p.m., 50 more, making 113 which hatched 
the first day. 



298 THE GYPSY MOTH. 

February 24, at noon, 80 more eggs had hatched ; at 5 
p.m., 43 more from the same cluster, or 123 on the second 
day. 

February 25, at 10 a.m., 20 more eggs had hatched; at 
1.15 p.m., 47 more; and at 6.15 p.m., 6 more, making 73 
eggs which hatched on the third day. 

February 26, at 7.30 a.m., 87 more had hatched; at 1.30 
p.m., 172, and at 5 p.m., 16 more, or 275 on the fourth day. 

February 27, at 7 a.m., 39 more had hatched ; and at 5.40 
p.m., 43 more, making 82 for the fifth day. 

February 28, at 7 a.m., 2; at noon, 26 ; at 5 p.m., no 
more had hatched, making 28 eggs which hatched on the 
sixth day. 

March 1, at 7 a.m., 2 more eggs had hatched; at noon, 5 ; 
and at 5 p.m., 2 more, making 9 for the seventh day. 

March 2, at 7.20 a.m., 1 more egg had hatched; and at 
5 p.m., 1 more, making 2 that hatched on the eighth day. 

March 3, at 7.45 a.m., 1 more egg had hatched. No other 
eggs hatched from this cluster. The total number of eggs 
hatched from the cluster, in nine days, was 706. From 
another egg-cluster, kept under similar conditions, 997 
hatched in eleven days. 

To gain further information concerning the actual number 
of caterpillars which may hatch from one egg-cluster, and the 
time required for hatching, a number of egg-masses which 
had been taken from the field were brought into a warm 
room and placed in boxes, April 25, 1895. The caterpillars 
were counted and then removed as soon as hatched. From 
egg-cluster No. 1, 250 caterpillars were hatched in 2 days and 
22 hours. From egg-cluster No. 2, 408 caterpillars were 
hatched in 3 days, 17 hours and 10 minutes. From egg- 
cluster No. 3, 708 caterpillars were hatched in 3 days, 17 
hours and 15 minutes. From egg-cluster No. 4, 679 cater- 
pillars were hatched in 3 days and 1 hour. From egg- 
cluster No. 5, 393 caterpillars were hatched in 3 days, 22 
hours and 30 minutes. From egg-cluster No. 6, 438 cater- 
pillars were hatched in 4 days, 16 hours and 45 minutes. 
The whole number of caterpillars from the six egg-clusters 
was 2,876, an average of 479 to each cluster. The average 
time in hatching was 3 days, 20 hours and 6| minutes. 



THE CATERPILLAR. 299 

From studies made on a large number of es^-clusters in 
the insectary, supplemented by observations in the field, it 
was discovered that in many eases some part of the eggs 
composing an egg-cluster did not hatch. Seven large egg- 
clusters which had hatched were found to contain on an 
average 124 unhatched eggs, the smallest number being 43, 
the largest 224. A small number of unhatched eggs is found 
in nearly all the old nests taken in the field. 

The Larva or Caterpillar. 

Relative Vitality of Caterpillars hatching at Different Times 
from the Same Egg-cluster. 

The following observations were made under my directions 
by Messrs. Minott and Mosher, both careful and reliable 
observers : — 

From a large cluster of eggs, laid by a single female 
gypsy moth, and kept in a warm room, 4 hatched late in the 
afternoon of March 11, 1894; at 10 a.m., March 13, 333 
more eggs had hatched ; at 5.20 p.m., 194 more had hatched ; 
March 14, 233 had hatched; March 15, at 4 35 p.m., 48 
more eggs had hatched; March 19, 10 more hatched; March 
20, 3 ; and on the 21st, 6 more eggs hatched, making 831 
eggs hatched from this cluster. The caterpillars were re- 
moved as soon as hatched. 

Fifty caterpillars were selected, as follows: 10 of those 
hatched on the second day, 10 of those hatched on the third 
day, 10 of those hatched on the fourth, 10 of those hatched 
on the eighth and 5 of those hatched on the ninth and tenth 
days, making 6 sets of caterpillars taken from those which 
hatched at different times. Each caterpillar was fed on let- 
tuce, in a box by itself, and under as nearly similar con- 
ditions as possible, careful records being made, for the pur- 
pose of learning whether there was any difference in the 
vitality of caterpillars hatched at different times, from the 
same egg-cluster ; the period of rest before and after each 
molt, and the time between each molt. No perceptible dif- 
ference was noticed in the vitality of those hatched at differ- 
ent times. It was observed that they all ate equally well 
and appeared equally healthy, and that all their transforma- 



300 THE GYPSY MOTH. 

tions agreed very closely, except that those which hatched 
latest did not require as many days in their molts, and there- 
fore reached the adult stage as soon as the others, although 
marked variations occurred among the individuals of each 
hatch (Plate 43) . Some grew faster than others, while some 
appeared to eat about the same amount as others and yet did 
not grow as rapidly. 

Description of the Larva or Caterpillar. 

The following descriptions were prepared from the study 
of from twenty-five to fifty caterpillars in each stage : — 

First Larval /Stage. — The larva, when first hatched, is 
3.6 mm. (about fourteen hundredths of an inch) in length, and 
the head is .6 mm. (about twenty-three thousandths of an inch) 
in width and somewhat thicker than the body, shining black, 
with a few (about forty) pale-yellow hairs scattered over the 
surface, the longest of which are not quite equal to the width 
of the head. There are a few additional hairs on the mouth 
parts. The body is more or less cylindrical, slightly taper- 
ing toward the posterior part which is blunt and rounded. 
When first hatched they are a pale' brownish-yellow, with a 
brown spot on the forward side of segments four to twelve 
inclusive, on the subdorsal line of each side, but the ground 
color grows darker within a few hours. The subdorsal tuber- 
cles of the second segment (first after the head) are elon- 
gated laterally and joined at the dorsal line. These are of 
a dark-brown color. The lateral tubercles of this segment 
are fused, forming one very large lateral tubercle on each 
side, which extends obliquely out and forward. The third 
and fourth segments have three tubercles on each side, one 
subdorsal, one lateral and one stigmatal. The remaining 
segments, except the last, have large subdorsal and lateral 
tubercles, the latter being so large as to fuse more or less 
completely with those above them. There are three nearly 
equal-sized tubercles on each side of the last segment, so 
arranged as to form an arched row around the posterior end 
of the animal. 

The insect at this stage has two kinds of hairs arising 
from the tubercles, the first of which (Plate 48, Fig. 8) is 
about as long as the thickness of the body, of a pale-brown 




PLATE 43. Variation in size of caterpillars of the same age. 
Fifty caterpillars hatched from the same egg-cluster 
were reared separately on lettuce leaves, all receiving 
exactly the same treatment. When the caterpillars were 
five weeks old, the two extremes in size, together with 
a caterpillar of medium size, were photographed. The 
smallest caterpillar as here shown has not molted. The 
medium caterpillar has molted twice. The largest has 
molted four times and is approaching the fifth molt. 



THE CATERPILLAR. 301 

color, smooth throughout, with a sharp point at the outer 
end; and at the basal third they have an inflated globule, 
the diameter of which is three times as great as that of the 
hair. The walls of this globule are delicate, and when the 
insect is alive they are fully distended, probably with air or 
gas ; but when dead they collapse more or less completely, 
often causing the hair to be bent at this place. The first 
and second rows of tubercles on each side have only hairs 
of this kind on them. Similar hairs occur on the larva of 
the nun moth (Lymantria monacha) before the first molt, 
and have been called aerostatic hairs by Wachtl and Kor- 
nauth, and the globules asrophores. These authors believe 
that these inflated globules have the effect of small balloons, 
and aid in transporting the young caterpillars to a consid- 
erable distance when the wind blows. The other kind of 
hairs (filiform hairs) (Plate 48, Fig. 9) arise from the two 
lateral rows of protuberances, and are unusually long, some 
of them being longer than the body of the caterpillar ; and 
they have several longitudinal rows of minute barbs extend- 
ing the entire length. 

Later the caterpillar changes color, the tubercles becoming 
black, the body reddish-brown with a row of dull reddish 
spots along the middle of the back, one each on the fifth 
to the eleventh segments inclusive. There are no retractile 
tubercles in this stage. 

The time between hatching and the first molt, of twelve 
caterpillars bred in confinement, in an unheated room, was 
from eight to twelve days, the average being nine and one- 
fourth days. The temperature very materially affects the 
time before molting, for, when caterpillars were kept in 
breeding cages near warm steam pipes, they molted in five 
days ; while others, from the same egg-cluster, kept in a 
cool part of the room, molted in seven days. 

Second Larval Stage. — Length, 7 mm. (about twenty- 
seven hundredths of an inch), and the head is 1 mm. (about 
thirty-nine thousandths of an inch) in width, shining black, 
with numerous fine, pale-yellow hairs scattered over the sur- 
face. Body, dark brown, with the tubercles black, and a 
somewhat triangular yellowish spot on the top of segments 
nine, ten and eleven, in the middle of which, on segments ten 



302 THE GYPSY MOTH. 

and eleven, there is an orange-colored retractile tubercle, and 
also one on each side of the dorsal line, near the front edge 
of segments five, six, seven and eight, of the same color, but 
much smaller. There are four rows of tubercles on each side, 
which, named from above, may be called the subdorsal, the 
lateral, the stigmatal and the substigmatal row, each with one 
tubercle on each segment after the head. The tubercles of 
the subdorsal rows on the second segment (first after the 
head), on the front half of the segment, are subquadrate in 
form, and but slightly separated from each other by the dorsal 
line. The subdorsal tubercles of the third and fourth sear- 
ments are smaller, and nearly elliptical in outline, while 
those on the remaining segments are larger and more nearly 
circular. The tubercles of the lateral row are smaller than 
those above, and on segments five to thirteen inclusive they 
are partially fused with those of the stigmatal row ; but as 
they are a little further forward than those below, the fusion 
gives an obliquely elongated tubercle. To effect this fusion 
the tubercles of these two rows are brought towards each 
other. The tubercle of the stigmatal row, on the second seg- 
ment, is large, somewhat produced, and directed obliquely 
forward. The substigmatal row consists of medium-sized 
tubercles, lying directly above the legs and prolegs, and 
about half-way between them and the stigmatal row. A little 
below, and behind these tubercles, on segments seven to 
eleven inclusive, is a very small tubercle, and on segments 
five, six, eleven and twelve there are two small tubercles on 
each side beneath, the inner ones being much the smaller. 
The tubercles of the subdorsal and lateral rows are armed 
with black, pointed spines and a few pale-yellow hairs, while 
the remaining tubercles are armed with longer pale-yellow 
hairs. On each side of the dorsal line, near the subdorsal 
tubercles, on segments three to twelve inclusive, is a very 
small tubercle, with one black spine and occasionally a few 
pale-yellow hairs. 

Third Larval Stage. — Length, 10 mm. (a little less than 
one-half of an inch), immediately after molting, and the 
head is 1.8 mm. (about seven hundredths of an inch) in 
width, shining black, with numerous pale-yellow hairs scat- 
tered over the surface. The general color of the body is 



THE CATERPILLAR. 303 

dark brown and very much broken, giving the appearance 
of a large spot on each segment. The lateral lines are dull 
yellowish- white. Arrangement of tubercles, bristles and 
hairs as in the last stage. 

Fourth Larval Stage. — Length, 13 mm. (about half an 
inch), immediately after molting, and the head is 2.8 mm. 
(about eleven hundredths of an inch) in width, pale brown- 
ish-white, mottled on the sides and above with dark brown, 
and there is a dark-brown vertical stripe on each side of the 
clypeus and numerous pale-yellow hairs scattered over the 
surface. The body is dark brown, finely mottled with yel- 
low ; while the dorsal line is pale ochre-reddish, enlarged 
into small grayish spots on the middle of the sixth, seventh 
and eighth segments, and on the ninth, tenth and eleventh 
segments there are larger orange-colored spots. The lat- 
eral line is pale yellow, and below this the surface is ashy, 
mottled with dark brown. The tubercles, spines and hairs 
are as in the preceding stage. 

Fifth Larval Stage. — Length, 23 mm. (about nine-tenths 
of an inch), immediately after molting. The head is 3.6 to 
4.4 mm. (about fourteen to seventeen hundredths of an 
inch) in width, or about the same width as the following 
segments without the lateral tubercles. The ground color 
is cream- white, and there is a vertical, velvety-black stripe 
on each side of the clypeus, outside and above which, the 
surface is sprinkled more or less thickly with velvety-black 
dots, which are more or less confluent. The labrum and 
mandibles are of a watery, whitish color, and the mouth 
parts beneath are dull reddish. Scattered over the surface 
are numerous pale-yellow setaceous hairs, varying in length 
from the width of the head to half that length. The upper 
surface of the body is cream-white, marked with black in 
minute, irregularly formed spots, giving a general dark-gray 
color, but leaving the dorsal line of a lighter color. The 
subdorsal tubercles, on segments two to six inclusive, are 
blue, and those on segments seven to twelve inclusive, are 
red. All the tubercles and retractile tubercles are of the 
same form, and arranged the same as in the last two stages ; 
the spines and hairs are also like those in the preceding 
stage. The fleshy, retractile tubercles on the dorsum of 



304 THE GYPSY MOTH. 

the tenth and eleventh segments usually have a convex cap 
of hardened reddish fluid, which may be removed with the 
point of a needle, and beneath which the tubercle is hollow 
to the depth of three or four mm., and filled with a reddish 
fluid, which has an agreeable odor, but I am not able to state 
what it is like. 

Sixth Larval Stage. — Length, 30 mm. (about one and 
eighteen hundredths inches), immediately after molting. 
The head is from 5.5 to 6 mm. (about twenty-two hun- 
dredths of an inch) in width, dull or yellowish white, and 
more or less mottled with black or brown over the top and 
sides, with a vertical black or brown stripe on each side of 
the clypeus. There is a great variation in the ground color, 
and also in the amount of black or brown on the surface of 
the head. Fine yellow hairs are scattered over the surface, 
and the color and markings are as in the preceding stage. 

Seventh Larval Stage. — Length, from 35 to 40 mm. 
There is no marked difference in appearance, in this stage, 
from the preceding, except in size, and all caterpillars that 
we have bred to this stage have transformed into female 
moths. Only a comparatively small proportion of the cater- 
pillars reach this stage before pupating. 

First and Last Appearance of Larva. 

The newly hatched caterpillars of the gypsy moth have 
been found in the field as early as April 20, and as late as 
June 17. In the summer of 1893, Mr. H. N. Reid found a 
caterpillar which did not begin to pupate until September 6. 
The feeding period of the caterpillar generally extends from 
the first of May, to about the middle of July, but varies 
somewhat with the season, and, in a less degree, with the 
locality of the colony, those near the sea-shore being some- 
what slower in development than those farther inland. 

Molts. 
In the latter part of the winter of 1893, Miss Carrie Gor- 
don, one of the assistants at the Maiden office, observed the 
molts of several caterpillars of the gypsy moth, taken from 
egg-clusters which had been kept in a warm room, and thus 



MOLTING. 305 

caused to hatch earlier than they otherwise would have done. 
The caterpillars were fed on the leaves of lettuce, and four 
of them completed their transformations, — two males and 
two females, — while three more died in pupating. The 
males molted five times and the females six times. Wishing 
to determine whether there would be any difference between 
these caterpillars, hatched out of season, and those reared 
under normal conditions, twelve newly hatched caterpillars 
of the gypsy moth, each in a separate box, were given to 
Miss Rose Davis, one of my assistants, early in May, 1893. 
These were fed on apple leaves, and each molt carefully 
noted. Of this lot, seven females molted five times, one 
female molted four times and four males molted four times. 
As these results differed so materially from those of Miss 
Gordon, I took fifty-five newly hatched caterpillars in May, 
1894, fed each on apple leaves, in a separate box, and care- 
fully observed the molts myself. Fifty-two of these cater- 
pillars completed their transformations, with the following 
results : one female molted six times, twenty-nine females 
molted five times and nine females molted four times ; seven 
males molted five times and six males molted four times. 
These results showed that in all probability no mistakes 
were made by the other observers, and also that the process 
of forcing the caterpillars makes no difference in the number 
of molts, though the small number carried through by Miss 
Gordon fails to make this point as conclusive as might be 
desired. 

The time between the hatching of the eggs, which occurred 
Feb. 3, 1893, and the first molt, and also between the 
remaining molts, is as follows, according to Miss Gordon's 
observations : — 

From the time of hatching till the first molt, 6 days. 
From the time of the first till the second molt, 7, 8 and 9 days. 
From the time of the second till the third molt, 6 and 7 days. 
From the time of the third till the fourth molt, 5, 6 and 7 days. 
From the time of the fourth till the fifth molt, 6, 7 and 8 days. 
From the time of the fifth till the sixth molt, 8 days. 

According to Miss Davis' observations, the time between 
the hatching of the eggs, which occurred May 7 and 8, 1893, 



306 



THE GYPSY MOTH. 



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MOLTING. 



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308 THE GYPSY MOTH. 

and the first molt, and also between the remaining molts, is 
as follows : — 

From the time of hatching till the first molt, 8, 9, 10 and 11 
days. 

From the time of the first till the second molt, 7 and 8 days. 
From the time of the second till the third molt, 7 and 8 days. 
From the time of the third till the fourth molt, 6, 7 and 8 days. 
From the time of the fourth till the fifth molt, 7, 8 and 9 days. 

According to my own observations, the time between the 
hatching of the eggs, which occurred April 28 and 29, 1894, 
and the first molt, and also between the remaining molts, is 
as follows : — 

From the time of hatching till the first molt, 9, 10 and 11 days. 
From the time of the first till the second molt, 11 days. 
From the time of the second till the third molt, 5, 6 and 7 days. 
From the time of the third till the fourth molt, 10 and 11 days. 
From the time of the fourth till the fifth molt, 8, 9 and 10 days. 
From the time of the fifth till the sixth molt, 13 days. 

The Process of Molting. 

When preparing to molt the young caterpillars remain 
quiet for twenty-four hours or more. The head is withdrawn 
from the old head covering, giving the caterpillar the appear- 
ance of having a very small head. The skin behind the head 
covering is ruptured, and the caterpillar crawls out of it, the 
whole process occupying not more than two minutes. Imme- 
diately after molting the long hairs of the body are curled up 
considerably, but gradually straighten out in about an hour. 
At intervals of about five minutes the caterpillar twists about, 
bringing the head to the right and left and upwards and 
backwards, nearly to the posterior end of the body, as if 
stretching itself or trying its muscles. The head grows per- 
ceptibly darker, even within an hour from the time of molt- 
ing, and in a few hours the head becomes black and shining 
and the caterpillar commences feeding. 

The approach of the molting period, in the later molts, is 
indicated by the development of a light-colored area, which 
forms behind the head during three or four days preceding 



PKOCESS OF MOLTING. 309 

molting. This area, which is but a narrow transverse line at 
first, gradually widens and extends down each side of the 
posterior margin of the head. It is widest on the dorsal line, 
and is formed by the separation and projection forward of 
the old chitinous covering of the head, while below and 
beneath, the new light-colored head covering becomes visi- 
ble. The light-colored area is apparently the top of the head 
drawn back from the old covering, and protected by the 
tightly stretched integument of the annulation. 

The caterpillar stops feeding usually from twenty-four to 
forty-eight hours before molting, and rests quietly except for 
occasional spasmodic twistings of the body. When the time 
for molting arrives, the integument splits on the ventral part 
of the annulation between the head and second segment and 
partly up the sides. The caterpillar clings by means of its 
pro legs to the surface on which it rests. It elevates the 
middle segments, depresses segments four and five and ele- 
vates the head and segments two and three. Its contortions, 
at this stage, somewhat resemble the travelling movements 
of a geometrid caterpillar, and, as the band over the light- 
colored area behind the head is very tenacious, the caterpillar 
bends itself nearly double ; the feet are then withdrawn by 
a series of successive movements ; with a few more con- 
tortions of the body sufficient force is developed to burst the 
band in the rear of the head, and the dorsal surface of the 
thoracic segments is molted. This stage requires about five 
minutes from the first separation of the integument. The 
head covering generally remains attached. 

By alternately contracting and expanding, the remaining 
segments are molted one after another. The last three seg- 
ments are generally molted in rapid succession, and the molt- 
ing, with the exception of the head, is completed in about 
fifteen minutes. After resting a few minutes the caterpillar 
begins to rid itself of the firm head covering. This is done 
by bending down the anterior segments, and then rubbing the 
top, front and sides of the head upon the surface to w T hich the 
caterpillar clings. Finally, the top of the head covering is 
loosened and pushed off. This process of molting the head 
requires from fifteen minutes to half an hour, and the whole 
process is completed in less than an hour. After molting 



310 THE GYPSY MOTH. 

the caterpillar raises its head and swings it from side to side, 
resting at intervals, and begins feeding in about twenty-four 
hours. The increase in the size of the body over that of the 
preceding molt, is more plainly noticed after the caterpillar 
has taken its first meal, but the increased size of the head is 
apparent at once. When first emerged from the molted skin 
the head is nearly cream-white, with faint darker markings, 
and all the colors of the body are light, but after a few 
hours they darken to the normal shades. The dorsal retrac- 
tile tubercles are very prominent immediately after molting, 
but regain their normal size in a short time. 

Caterpillars attracted to Light. 
When caterpillars hatch in hollow trees or other dark 
places, they invariably find their way out in a short time, 
being attracted, as it is supposed, towards the light. To 
determine how strongly the light influenced them in their 
movements, May 6, 1895, twenty-five newly hatched cater- 
pillars were placed in small pasteboard boxes which had a 
small hole in each end. One end of each box was placed in 
the bright sunlight, while the other end was shaded. In 
an hour and a half all the caterpillars had emerged through 
the holes in the ends exposed to the sun. 

Distance Young Caterpillars are able to Travel. 
For the purpose of ascertaining how far from the egg- 
cluster a newly hatched caterpillar can travel without feed- 
ing, seven were placed on a large sheet of white paper on a 
table. Their movements were traced by following them 
with the point of a pencil on the paper as they crawled, 
and these lines were carefully measured after the death of 
the caterpillars. In their movements it was observed that 
they showed a strong tendency to crawl towards the window 
during the day, and towards the light of the lamp during the 
night ; but in no case were they observed to be attracted 
towards food, however near it was placed, provided it did 
not touch their hairs. The distance travelled by each cater- 
pillar before it died was as follows : No. 1 travelled 90| 
feet ; No. 2, 93 feet ; No. 3, 143 feet ; No. 4, 85 feet ; No. 
5, 36 feet; No. 6, 46| feet; and No. 7, 144 feet; aver- 



CATERPILLAR TRAPS. 311 

age, about 91 feet. These observations have a bearing on 
the question of how far the trees around a colony should be 
burlapped. 

Caterpillar Traps. 

In the summer of 1895, at the suggestion of Mr. For- 
bush, several attempts were made to capture the caterpil- 
lars of the gypsy moth by means of traps, constructed with 
reference to their habit of seeking out cracks, crevices, etc., 
for shelter during the day. Different styles of traps were pre- 
pared, all made with small openings, closed by a fringe of 
hair-cloth or felt, through which the insect might enter but 
could not return. These traps were attached to the trunks 
of badly infested trees ; and, while they caught and retained 
a small number of caterpillars, as a whole they were not a 
success. 

When a number of old tin cans are placed along an 
infested hedge or wall, at the time the caterpillars are 
pupating, it has been found that they will enter them in 
large numbers and pupate. Females, emerging in these 
cans, deposit their eggs there ; and by frequent examination 
of the cans a large number of pupae and egg-clusters can be 
destroyed. 

Feeding Habits. 
In general, it may be said that the gypsy moth caterpillar 
is almost omnivorous so far as foliage is concerned, and its 
ability to adapt itself to nearly every food plant is one of 
the chief obstacles to its extermination. For this reason, 
also, it is capable of committing far greater depredations 
than any of our common native insects. A list of food 
plants attacked by the gypsy moth is given on succeeding 
pages, and, since the ravages of the insect on fruit and 
forest trees have been so fully described in Part I. of this 
report, we pass to a more detailed account of the feeding 
habits. The feeding habits of caterpillars of different ages 
are shown on Plate 40. 

Time and Manner of Feeding. 
To determine the time and manner of feeding of the cater- 
pillars, a series of observations was made by Mr. Minott in 



312 THE GYPSY MOTH. 

1893, and repeated by Mr. Kirkland in 1894. Many obser- 
vations had been made by different members of the force, 
but none were so extensive or complete as those made by 
these gentlemen, yet all agreed more or less in regard to 
the habits. To enable one to make observations on cater- 
pillars, on trees in the field or forest, it was necessary to 
have some system of marking ; and for this purpose water- 
colors were found to be excellent, and in no way injured the 
insects ; though, in the case of caterpillars which were to be 
continuously observed during the entire larval stage, it was, 
of course, necessary to reapply the color after each molt. 
Several different colors were used, especially those which 
contrasted strongly with the ground color of the caterpil- 
lars. 

From these observations it appears that the caterpillars 
remain on the egg-cluster, after hatching, from one to five 
or more days, according to the weather, when they wander 
off to the leaves and commence feeding. The first food 
is the leaf hairs, and, unless one observes very carefully, 
he might suppose that they do not feed until they are four 
or five days old; from this time on, however, one can see 
where they have eaten the tissues, making small holes 
through the leaf, though occasionally they eat from the 
edge ; but they are extremely irregular in their manner of 
feedinfif. Between the third and fourth molts their method 
of feeding is about equally divided between eating holes 
through the leaf and eating along the edge (Plates 40 and 
44). From the fourth molt till they are ready to pupate, 
they eat almost entirely from the edge of the leaf, though 
there are occasional exceptions to this. 

Mr. Kirkland's observations on full-grown caterpillars 
were made on the nights of July 7, 8 and 9, 1894. A me- 
dium-sized infested elm tree was selected, and all small twigs 
and branches that might interfere were removed. A band of 
burlap had been put around the trunk, about four feet from 
the ground. Twenty caterpillars, some partly and some 
fully grown, were under the burlap. Eight of these cater- 
pillars were marked with water-colors, in such a manner that 
they could be distinguished from each other as well as from 
those not marked. The caterpillars were numbered, and 




PLATE 44. Oak leaves eaten by the caterpillars of the gypsy moth. 
Taken from an infested tree, Saugus, July, 1894. 



TIME AND MANNER OF FEEDING. 313 

observations made every ten minutes, from 6 o'clock in the 
afternoon till 5 the next morning. At 7.30 p.m., caterpillar 
No. 4 began to grow uneasy, and moved about under the bur- 
lap or on the trunk below it. At 8.20 the first one, No. 2, 
started up the tree from the burlap, and soon all the rest 
were on the move. Some of the caterpillars, after climbing 
up the trunk several feet, descended for a short distance and 
then ascended again ; and they often stopped to rest on their 
way up or down the tree trunk. At 9.50 No. 3 had reached 
the leaves, sixteen feet from the burlap, and begun feeding. 
Others reached the leaves later, and fed during the night 
with intervals of rest. At about 3 a.m. they ceased feeding 
and descended the trunk, and at 4.25 all were at rest under 
the burlap or in crevices in the bark. One caterpillar about 
to molt and one about to pupate remained quietly under the 
burlap all night. It was further observed that the smaller 
caterpillars, as a rule, fed on the lower branches, while many 
of the larger ones went to the extreme tips of the upper 
limbs. 

Mr. Minott's observations were made on the nights of 
July 26, 27, 28 and 29, 1893; and the results were sub- 
stantially the same as in Mr. Kirkland's observations, except 
that the caterpillars started from their places of concealment 
to ascend the trees a little earlier in the evening. The 
observations of Mr. Kirkland, on a single caterpillar, will 
illustrate fairly well the operations of the insect during the 
night, though others varied slightly in their work : — 

P.M. 

7.40. Caterpillar came out from under the burlap and began 

moving up the tree. 
7.50. Ascended the trunk, twelve feet from the burlap. 
8.00. Reached a leaf fifteen feet from burlap and commenced 

feeding. 
8.10. Still feeding. 
8.20. Had three feeding spells between 8 and 8.15, with short 

rests between. 
8.30. Feeding. 
8.40. Moving. 
8.50. Feeding. 
9.00. Feeding. 



314 THE GYPSY MOTH. 

P.M. 

'J. 10. Feeding. It began at the base of the leaf, clasping the 
petiole and twig with feet and prolegs, eating the base 
of the leaf close to the midrib, then, raising its head, 
worked out toward the margin of the leaf, making a 
crescent-shaped cut, then started from the midrib 
again. 

9.20. Feeding. 

9.30. Resting, after having eaten steadily twenty-five minutes. 

9.40. Feeding (began at 9.31). The caterpillar then fed 
steadily until 11 p.m. 
11.00. Resting a few seconds, after feeding one and one-half 
hours. 

A.M. 

12.10. Feeding. Has fed continuously since 11.10; has eaten 
the whole of one side of a leaf and is now working 
upon the tip. 

12.20. Feeding upon the tip of the remaining half of the leaf. 
It begins at the midrib, actually eating it, then takes 
a strip square across the leaf to the margin, then 
begins eating again at the midrib. Sometimes it 
reverses this movement, and feeds from the margin 
to the midrib. 

12.30. Feeding. 

12.40. Feeding. 

12.50. Left the remains of its leaf, having eaten nearly all 
through it, and started at once upon the second. The 
caterpillar then fed without interruption until 3.20 

A.M. 

3.20. Stopped feeding, crawled out to the end of the twig, 

turned back and crawled down the main branch. 
3.30. Slowly descending (daylight approaching) . 
3.40. Descending. 

3.50. Descending, about four feet above the burlap. 
4.00. Descending. 

4.10. Crossed the burlap, crawled under it, and at once became 
quiet. 
Weather during the night, fair, cool and starlight. 

Summary. 
Detailed observations made on twenty-five caterpillars 
may be summarized as follows : — 




PLATE 45. Hornbeam and other trees stripped by the caterpillars 
of the gypsy moth, Swampscott, 1891. 



AMOUNT OF FOOD. 315 

1. The large caterpillars leave the burlap or other places 
of concealment for their places of feeding between 7 and 8 
o'clock in the evening, or sometimes a little later. 

2. They proceed by easy stages, resting frequently, 
from their places of concealment to the places of feeding, 
though some of them wander up and down the trees more 
or less. 

3. When the distance is short, they proceed directly to 
the leaves and begin feeding immediately. 

4. They feed and rest alternately, at frequent intervals 
during the nio;ht. 

5. As a rule, they go to the same feeding place each 
night and return to the same place of concealment, though 
they will accustom themselves to a new feeding place, 
especially in the younger stages. 

6. They cease feeding at daylight (between 3 and 4 
o'clock in the morning), but when it is cloudy they feed 
later. It would seem that the first indication of daylight 
is the signal for them to return to their places of con- 
cealment. 

Amount of Food consumed by Caterpillars. 
To learn the amount of food hungry caterpillars of dif- 
ferent ages would consume in twenty-four hours, the follow- 
ing experiment was made during the summer of 1895 : a 
known quantity of food was supplied to the caterpillars, 
and at the end of a specified time the remains of the leaves 
were carefully soaked in water and then measured. May 
10, at 4.30 p.m., three caterpillars, between the first and 
second molt, were placed in a breeding jar with 6 square 
inches of lettuce leaf. At 7.30 a.m., May 11, 4 square 
inches were added, making a total of 10 square inches. 
May 11, at 7.30 a.m., the refuse was removed, and equalled 
2 square inches, thus giving 8 square inches as the amount 
consumed by the three caterpillars, or 2| square inches per 
caterpillar for twenty-four hours. May 10, at 4.30 p.m., 
three caterpillars, between the second and third molt, were 
supplied with 9 square inches of lettuce leaf. The next 
morning 4 square inches were added, and at 1.30 p.m. 



316 THE GYPSY MOTH. 

2 square inches. The refuse, which was removed at 4.30 
p.m., measured 3 square inches, making 12 square inches 
which had been eaten by the three caterpillars, or 4 square 
inches per caterpillar. May 10, at 4.30 p.m., three cater- 
pillars, between the third and fourth molt, were supplied 
with lettuce as follows : May 10, at 4.30, 9 square inches ; 
May 11, at 7.30, 4 square inches; and at 1.30 p.m. 4 square 
inches : total, 17 square inches. The refuse was removed 
May 11, and measured 3 square inches, leaving 14 square 
inches as the amount consumed, or 4| square inches per 
caterpillar. Three caterpillars, between the fourth and fifth 
molt, were supplied with 18 square inches of lettuce at the 
same date and hour, and on May 11, at 7.30 a.m., 9 square 
inches were added; and at 1.30 p.m. 9 square inches more. 
The refuse, removed at 4.30 p.m., May 11, measured 5 
square inches, leaving 31 square inches the amount con- 
sumed by all, or 10^ square inches per caterpillar. June 26, 
three caterpillars, between the last molt and pupation, were 
given 20 square inches of lettuce leaf at 7 a.m., and at 
5 p.m., 20 square inches more were added. At 7 a.m., June 
27, the refuse was removed and soaked out. It then 
measured 5 square inches, making 35 square inches that had 
been eaten by the three caterpillars, or llf square inches 
per caterpillar. 

These figures give evidence of the food capacity of the 
caterpillars, but it should be borne in mind that lettuce does 
not offer so much resistance to the jaws (mandibles) of the 
caterpillar as do the harder leaves of the apple, oak and 
others. 

Food Plants. 

A series of experiments was conducted during the part of 
the season of 1895 that the gypsy moth was in the caterpillar 
stage, for the purpose of determining so far as possible all 
the plants this insect will feed upon. For this purpose col- 
lectors brought in specimens of all the plants met with in the 
fields and forests of the infested territory. To Mr. H. L. 
Frost, a careful student of botany as well as entomology, 
was assigned the work of determining these plants and carry- 
ing out the details of the experiment. While the plants were 



FOOD PLANTS. 317 

still fresh they were placed in eight-ounce glass jars, and four 
caterpillars, in the fourth or fifth molt, were placed upon them. 
This number was about all that could feed without crowd- 
ing, and at the same time give appreciable results before the 
plants wilted. The jars were covered at the top with thin 
cloth, to prevent the escape of the caterpillars and at the 
same time to allow ventilation. They were numbered, and 
the numbers, with the names of the plants, were booked at 
the time the caterpillars were placed on the food, the jars 
being kept in a place sufficiently cool to prevent undue evap- 
oration, but at a temperature at which the caterpillars fed 
readily. Observations were made every twenty-four hours, 
and, if at the end of three days the caterpillars showed an 
unwillingness to feed on the plant, the experiment was re- 
peated with a fresh stock of caterpillars on a fresh supply of 
the same food. If they did not attack it at the second trial, 
in view of their accustomed readiness to feed on nearly all 
plants, it was assumed that they would not feed on the plant 
in question. The flora of the region about Maiden is mari- 
time rather than inland, and some of the common plants 
of the central and western parts of the State do not occur 
there. 

Attention is called to the fact that the caterpillars of 
the gypsy moth feed readily on common water plants, 
such as JSFymphcea odorata, Pontederia cordata and Alisma 
plantago. Experiments performed this year proved that 
some of the caterpillars will live for several days floating 
on the water and without food. These two facts in connec- 
tion may help to explain the distribution of this insect along 
streams. 

In the following lists both the common and scientific 
names are given, as far as possible. The nomenclature is 
that of Gray's "Manual of Botany," 1889, for the wild 
plants, and Wood's "Botany" of 1889, for the cultivated 
plants. An asterisk before a name denotes that the cater- 
pillars fed on the plant only when forced to do so by 
starvation. It will be noticed that about twenty-one per 
cent, of the plants in the following list are of economic 
value. 



318 



THE GYPSY MOTH. 



Plants upon which the Gypsy Moth Caterpillar has been known to feed 
in Massachusetts. 



Virgin's bbwer {Clematis Virginiana). 
*Wind flower {Anemone Virginiana) . 
White water crowfoot {Ranunculus 

aquatilis, var. trichophyllus) . 
Small-flowered crowfoot {Ranunculus 

abortivus) . 
Hooked crowfoot {Ranunculus recur- 

vatus) . 
Bulbous crowfoot {Ranunculus bulbo- 

sus). 
"Wild columbine {Aquilegia Canaden- 
sis') . 
Peony {Paonia officinalis). 
Umbrella tree {Magnolia umbrella). 
"Magnolia Soulangeana. 
Tulip tree ( Liriodendron Tulipifera) . 
Siberian pea tree {Caragana arbores- 

cens) . 
Barberry {Berber is vulgaris). 
Holly barberry {Berberis Aquifolium) . 
White water lily {Nympha-a odorata) . 
Pitcher plant {Sarracenia purpurea) . 
Celandine {Chelidonium majus). 
Poppy {Papaver orientalis) . 
*Pale corydalis ( Corydalis glauca) . 
*Sweet alyssum {Alyssum maritimum) . 
Horseradish {Nasturtium Armoracia) . 
Hedge mustard {Sisymbrium officinale) . 
Black mustard {Brassica nigra). 
Turnip {Brassica rapa, var. depressa) . 
Savoy cabbage {Brassica oleracea, var. 

bullata) . 
Shepherd's purse {Capsella Bursa-pas- 

toris) . 
Wild peppergrass {Lepidium Virgini- 
cum) . 
*Sea rocket {Cakile Americana). 
Radish {Raphanus Raphanistrum) . 
Blue violet ( Viola palmata, var. cucul- 

lata) . 
Primrose-leaved violet ( Viola primuhe- 

folia). 
Lance-leaved violet {Viola lanceolata). 
Dog violet ( Viola canina, var. Muhlen- 

bergii) . 
Pansy ( Viola tricolor) . 
Carnation pink {Dianthus caryophyl- 

lus). 
•Sweet William {Dianthus barbatus). 
Bouncing bet ( Saponaria officinalis) . 
Corn cockle {Lychnis Githago). 
Common chickweed {Stellaria media). 
Mouse-ear chickweed {Cerastium vul- 
gatum) . 



Sand spurrey {Buda rubra). 
Purslane {Portulaca oleracea) . 
St. John's-wort {Hypericum perfor- 
atum) . 
Marsh St. John's-wort {Elodes campan- 

ulata) . 
Hollyhock {Althcea rosea) . 
Common mallow {Malva rotundifolia) . 
Indian mallow {Abutilon vexillarium) . 
*Chinese hibiscus {Hibiscus Rosa-Sinen- 
sis). 
Cotton plant ( Gossypium herbaceum) . 
Bass wood {Tilia Americana). 
European linden {Tilia Europcea). 
Wild cranesbill ( Geranium maculatum) . 
Geranium {Geranium sanguineum). 
Yellow wood sorrel {Oxalis corniculata, 

var. stricta). 
Nasturtium {Tropceolum majus). 
Spotted touch-me-not {Impatiensfulvd). 
Fraxinella {Dictamnus albus). 
*Shrubby trefoil {Ptelea trifoliata). 
*Lemon ( Citrus Limonum) . 
Tree of Heaven {Ailanthus glandulo- 

sus). 
Black alder {Ilex verticillata) . 
Climbing bittersweet {Celastrxis scan- 
dens) . 
European spindle-tree {Euonymus 

Europa-u's) . 
Grape {Vitis rinifera). 
Northern fox grape {Vitis Labrusca). 
Virginian creeper {Ampelopsis quinque- 

folia) . 
Ampelopsis veitchii. 
Horse chestnut {JEsculus Hippocas- 

tanum). 
Red buckeye {JEsculus Pavia) . 
Sugar maple {Acer saccharinum) . 
White maple {Acer dasycarpum). 
Cut-leaved maple {Acer dasycarpum, 

var. Welrii). 
Red maple {Acer rubrum) . 
Sycamore maple {Acer Pseudo-Plat- 

anus) . 
Box elder {Negundo aceroides). 
Variegated box elder {Negundo acer- 
oides, var. variegata). 
Kosulreuteria paniculata. 
Stag-horn sumach {Rhus typhina). 
Smooth sumach {Rhus glabra) . 
Poison dogwood {Rhus venenata). 
Poison ivy {Rhus Toxicodendron). 
Rhus vernex. 



FOOD PLANTS. 



319 



Plants upon which the Gypsy Moth Caterpillar has been known to feed 
in Massachusetts — Continued. 



Smoke tree {Rhus Cotinus). 

Milkwort {Poly gala polygama). 

Wild indigo {Baptisia tinctoria). 

Yellow wood {Cladrastis lutea). 

Dyer's green weed ( Genista tinctoria) . 

Rabbit-foot clover {Trifolium arvense). 

White clover {Trifolium repens). 

Red clover {Trifolium pratense) . 

Alsike clover {Trifolium hybridum). 

Yellow clover {Trifolium agrarium). 

Low hop clover (Trifolium procumbens) . 

False indigo {Amorpha fruticosa) . 

Locust (Robinia Pseudacacia). 

Wistaria ( Wistaria consequana) . 

Tick trefoil {Desmodium nudijlorum). 

Common vetch ( Vicia sativa) . 

Beach pea {Lathy rus maritimus). 

Ground-nut {Apios tuberosa). 

Scarlet pole bean {Phaseolus multi- 
Jlorus) . 

Bush bean ( Phaseolus nanus) . 

Red bud {Cercis Canadensis). 

Kentucky coffee tree {Gymnocladus 
Canadensis) . 

Honey locust {Gleditschia triacanthos) . 

Chinese honey locust {Gleditschia Si- 
nensis) . 

Coffee bean ( Faba vulgaris) . 

Pea {Pisum sativum). 

Cercidipkyllum Japonicum. 

Beach plum {Primus maritima). 

Wild red cherry {Prunus Pennsylvan- 
ica) . 

Choke cherry {Prunus Virginiana). 

Wild black cherry {Prunus serotina). 

Damson plum {Prunus domestica). 

English cherry {Prunus Avium). 

Peach {Prunus vulgaris). 

Purple-leaved plum {Prunus Pissardi). 

Prunus Davidii. 

Apricot {Prunus Armeniaca). 

Japanese plum {Prunus Jajwnica) . 

Meadow sweet {Spiraea salicifolia) . 

Hardhack {Spiraea tomentosa) . 

Spiraea Thunbergii. 

Purple flowering raspberry {Rubus 
odoratus) . 

Dwarf raspberry ( Rubus triflorus) . 

Wild red raspberry {Rubus strigosus). 

Thimbleberry ( Rubus occidentalis) . 

High blackberry {Rubus villosus). 

Low blackberry {Rubus Canadensis). 
•Avens {Geum macrophyllum). 

Strawberry {Frag aria Virginiana). 



*Cinquefoil {Potentilla Norvegica). 

Silvery cinquefoil {Potentilla argen- 
tea). 

Common cinquefoil {Potentilla Can- 
adensis) . 

Shrubby cinquefoil {Potentilla fruti- 
cosa) . 

Agrimony {Agrimonia Eupatoria). 

Prairie rose {Rosa setigera). 

Dwarf wild rose {Rosa lucida). 

Rose {Rosa nitida) . 

Crab apple {Pyrus coronaria). 

Narrow-leaved crab apple (Pyrus an- 
gustifolia) . 

Choke berry ( Pyrus arbutifolia) . 

American mountain ash {Pyrus Amer- 
icana) . 

Pyrus sambuci folia. 

Pyrus pinnatifida. 

Pyrus decata. 

Pear {Pyrus communis). 

Apple {Pyrus Malus). 

English hawthorn {Crataegus Oxyacan- 
tha). 

Paul's thorn {Crataegus coccinea, var. 
Paulii) . 

Cockspur thorn ( Crataegus Crus-galli) . 

Shad bush {Amelanchier Canadensis). 

Amelanchier alnifolia. 

Quince {Cydonia vulgaris). 

Japan quince ( Cydonia Japonica) . 
*Sweet-scented shrub {Calycanthusfio- 
ridus) . 

Mock orange {Philadelphus coronarius) . 
*Deutzia gracilis. 

Hydrangea paniculata. 

Common red currant {Ribes rubrum). 

Black currant {Ribes nigrum). 

Gooseberry {Ribes grossularia) . 

English gooseberry {Ribes Uva-crispa). 

Ditch stonecrop ( Penthorum sedoides) . 

Garden orpine {Sedum Telephium). 

Witch hazel {Eamamelis Virginiana). 

Sweet gum tree {Liquidambar Styraci- 
Jlua). 

Swamp loosestrife {Decodon verticil- 
latus) . 

Pomegranate {Punica granatum) . 

Great willow herb {Epilobium angusti- 
folium) . 

Slender willow herb {Epilobium lin- 
ear e). 

Common evening primrose {Oenothera 
biennis) . 



320 



THE GYPSY MOTH. 



Plants upon which the Gypsy Moth Caterpillar has been known to feed 
in Massachusetts — Continued. 



Evening primrose (Oenothera pumila). 
Ladies' eardrop (Fuchsia coccinea). 
Squash (Cucurbita verrucosa) . 
Cucumber (Cucumis sativus). 
•Parsnip (Peucedanum sativum). 
Zizia aurea. 

Celery (Apium graveolens). 
Spotted cowbane (Cicuta maculata). 
Hercules' club (Aralia spmosa) . 
Wild sarsaparilla (Aralia nudicaulis) . 
Flowering dogwood (Cornus Jtorida) . 
Cornus mas. 

Common elder (Sambucus Canadensis) . 
Cranberry tree ( Viburnum Opulus) . 
Arrowwood (Viburnum acerifolium) . 
Downy arrowwood ( Viburnum pubes- 

cens) . 
Arrowwood ( Viburnum dentatum) . 
Viburnum tomentosum. 
Sweet viburnum ( Viburnum Lentago) . 
Black haw ( Viburnum prunifolium) . 
Wayfaring tree ( Viburnum Lantana) . 
Snow berry (Sympihoricarpius racemo- 

sus). 
Trumpet honeysuckle (Lonicera sem- 

pervirens) . 
Bush honeysuckle (Diervilla trifida). 
Wiegelia rosea. 
Button bush (Cephalanthus occiden- 

talis) . 
Partridge berry (Mitchella repens). 
Small bedstraw (Galium trifidum). 
Rough bedstraw (Galium asprellum) . 
Joe pye weed (Eupatorium purpureum) . 
Thoroughwort (Eupatorium perfolia- 

tuni) . 
Golden-rod (Solidago rugosa). 
Golden-rod (Solidago arguta). 
*Golden-rod (Solidago Canade?isis) . 
Golden-rod (Solidago lanceolata). 
Aster undulatus. 
Aster cordifolius. 
Aster leevis. 
Aster puniceus. 
Aster miser. 

Horse weed (Erigeron Canadensis). 
Fleabane (Erigeron Philadelphicus). 
Elecampane (Inula Helenium) . 
Roman wormwood (Ambrosia artemis- 

icefolia) . 
Cone flower (Rudbeckia hirta). 
Sunflower ( Helianthus annuus) . 
*Helianthus decapetalus. 
Artichoke (Helianthus tuber osus) . 



Beggar ticks (Bidens frondosa) . 

Bur marigold (Bidens chrysanthe- 

moides) . 
May weed (Anthemis Cotula). 
Yarrow (Achillea Millefolium). 
Ox-eye daisy (Chrysanthemum Leu- 

canthemum). 
Chrysanthemum (Chrysanthemum Si- 

nense) . 
Tansy (Tanacetum vulgare) . 
Fireweed (Erechtites hieracifolia) . 
Burdock (Arctium Lappa). 
Common thistle (Cnicus lanceolatus) . 
Tall thistle (Cnicus altissimus). 
Canada thistle (Cnicus arvensis). 
Dwarf dandelion (Krigia Virginica). 
Chicory (Cichorium Intybus). 
Fall dandelion (Leonlodnn autumnale) . 
Rattlesnake root (Prenanthes alt is- 

sima) . 
*White lettuce (Prenanthes alba). 
Dandelion (Taraxacum officinale). 
Lettuce (Lactuca sativa). 
Common dahlia (Dahlia variabilis) . 
French marigold (Tagetes patula) . 
Indian tobacco (Lobelia infiata). 
Lobelia spicata. 
Venus' looking glass (Specularia per- 

foliata) . 
Dangleberry (Gaylussacia frondosa) . 
Black huckleberry (Gaylussacia resin- 

osa). 
Dwarf blueberry ( Vaccinium Pennsyl- 

vanicum) . 
Low blueberry (Vaccinium vacillans) . 
Swamp blueberry (Vaccinium corym- 

bosum) . 
Leather leaf (Cassandra calyculata). 
Sheep laurel (Kalmia angustifolia) . 
Clammy azalea (Rhododendron- visco- 

sum) . 
Rhodora (Rhododendron Rhodora). 
Great laurel (Rhododendron maximum). 
Labrador tea (Ledum latifolium). 
Sweet pepperbush ( Clethra alnifolia) . 
Prince's pine (Chimaphila umbellata) . 
Shin leaf (Pyrola elliptica). 
Pyrola rotundifolia. 
Star flower (Trienialis Americana). 
Steironema ciliatum. 
Loosestrife (Lysimachia quadrifolia) . 
Sweet leaf (Symplocos cratagoides) . 
White ash (Fraxinus Americana). 
Red ash (Fraxinus pubescent). 



FOOD PLANTS. 



321 



Plants upon tvhich the Gypsy Moth Caterpillar has been known to feed 
in Massachusetts — Continued. 



Blue ash (Fraxinus quadrangulata) . 

Black ash (Fraxinus sambucifolia) . 

European ash {Fraxinus excelsior). 

Fraxinus Oregona. 

Fraxinus rhijcophylla. 

Fraxinus Sag-Diana. 

Fringe tree (Chionanthus Virginica). 

Privet (Ligustrum vulgare). 

Common lilac (Syringa vulgaris). 

Japanese lilac {Syringa Japonica) . 

Forsyth ia viridissima. 

Dogbane (Apocynumandrosfvmifolium). 

Swamp milkweed {Asclepias incarnata) . 

Common mtikweed(Asclepias Cornuti) . 

Poke milkweed {Asclepias phytolac- 

coides) . 
Forget-me-not (Myosotis arvensis). 
Heliotrope ( Heliotropium Peruvianum) . 
Morning glory (Ipomcea purpurea) . 
Dodder {Cuscuta Gronorii). 
Bittersweet {Solanum Dulcamara). 
Potato {Solatium tuberosum). 

Petunia nyctagini folia. 

Tomato {hy coper sicutn esculentum). 

Matrimony vine (Lycium vulgare). 
♦Virginia tobacco (Nicotiana Tabacum) . 

Xicotiana longiftora. 

Mullein ( Verbascum Thapsus). 

Toad flax {Linaria Canadensis). 

Butter and eggs {Linaria vulgaris). 
*Monkey flower {Mimulus ringens) 

Water speedwell ( Veronica Anagallis) . 
*Purple gerardia {Gerardia purpurea) . 

Trumpet creeper {Tecoma radicans). 

Catalpa (Cataljia bignonioides). 
* White vervain {Verbena urticcefolia). 
*Blue vervain ( Verbena hastata). 

Spearmint {Mentha viridis) . 

Peppermint {Mentha piperita) . 

Bugle weed {Lycopits Virginicus). 

Catnip {Nepeta Cataria). 

Self heal {Brunella vulgaris) . 

Dead nettle {Lamium album). 

Scarlet sage {Salvia splendens) . 

Common plantain {Plantago major). 

Seaside plantain ( Plantago maritima) . 

Green amaranth {Amarantus retro- 
Jlexus) . 

Pigweed {Chenopodium album). 

Coast blite {Chenopodium rubrum). 

Spinach {Spinacia oleracea) . 

Beet {Beta vulgaris). 

Garget {Phytolacca decandra). 

Patience dock {Rumex Patientia). 



Swamp dock {Rumex verticillatus) . 
Curled dock ( Rumex crispus) . 
Sheep sorrel {Rumex Acetosella) . 
Rhubarb {Rheum Rhaponticum). 
Coast knotgrass {Polygonum mariti- 

mum). 
Door weed {Polygonum aviculare). 
Polygonum Pennsylvan icum. 
Water persicaria {Polygonum amphib- 

ium) . 
Polygonum Careyi. 

Lady's thumb {Polygonum Persicaria). 
Water pepper {Polygonum hydropiper- 

oides) . 
Smart weed {Polygonum Hydropiper) . 

Arrow-leaved tear thumb {Polygonum 
sagittatum) . 

Sassafras {Sassafras officinale). 

Oleaster {El&agnus hortensis). 

Elceagnus Longipes. 

Elceagnus umbellata. 

Spurge {Euphorbia Cyparissias) . 

Slippery elm ( Ulmus fulvus) . 

White elm ( Ulmus Americana) . 

Cork elm {Ulmus racemosa). 

English elm {Ulmus campestris). 

Scotch elm {Ulmus montana). 

Common hop ( Humulus Lupulus) . 

Red mulberry {Moms rubra). 

Tartarian mulberry {Morus Tartarica). 

Nettle ( Urtica gracilis) . 

Nettle {Urtica dioioa). 

India rubber tree {Ficus elastica). 

Sycamore {Platanus occidentalis) . 

Butternut {Juglans cinerea). 

Shell-bark hickory ( Carya alba) . 

White-heart hickory ( Carya tomentosa) . 

Pignut {Carya porcina) . 

Bayberry {Myrica cerifera). 

Sweet fern {Myrica asplenifolia) . 

Black birch {Betula lenta) . 

Yellow birch {Betula lutea). 

White birch {Betula populifolia) . 

Paper birch {Betula papyrif era) . 

River birch {Betula nigra). 

Cut-leaved birch {Betula alba, var. 

laciniata) . 
Betula Danurica. 

Speckled alder {Alnus incana). 
Smooth alder (Alnus serrulata). 

Wild hazelnut {Corylus Americana). 
Hop hornbeam ( Ostrya Virginica). 
White oak ( Quercus alba) . 
Swamp white oak {Quercus bicolor). 



322 



THE GYPSY MOTH. 



Plants upon which the Gypsy Moth Caterpillar has been known to feed 
in Massachusetts — Concluded. 



Red oak (Quercus rubra). 

Scarlet oak (Quercus coccinea). 

Black oak (Quercus coccinea, var. tinc- 
torial) . 

Pin oak ( Quercus palustris) . 

Scrub oak ( Quercus ilici folia) . 

Barren oak (Quercus nigra). 

Chestnut (Castanea sativa, var. Ameri- 
cana) . 

Chinquapin ( Castanea pumila) . 

Blue beech ( Garpinus Caroliniana) . 

American beech (Fagus ferruginea) . 

Purple beech (Fagus sylvatica, var. 
purpurea) . 

Crack willow (Salix fragilis) . 

White willow (Salix alba). 

Weeping willow (Salix Babylonica). 

Heart-leaved willow (Salix cordata). 

White poplar (Populus alba). 

American aspen (Populus tremuloides) . 

Large-toothed aspen (Populus grandi- 
dentata) . 

Balm of Gilead (Populus balsamifera, 
var. candicans). 

Black poplar (Populus nigra). 

Lonibardy poplar (Populus nigra, var. 
dilatata) . 

White pine (Pinus Strobus). 

Pitch pine (Pinus rigida). 

Scotch pine (Pinus sylvestris). 

White spruce (Picea alba). 

Norway spruce (Picea excelsa) . 

Fir (Abies balsamea) . 

Hemlock (Tsuga Canadensis). 

Larch (Larix Americana). 

European larch (Larix Europa>a). 

Arbor vita? (Thuja occidentalis) . 

Common juniper (Juniperus communis) . 

Red cedar (Juniperus Virginiana). 
*Ginkgo (Juniperus Salisburia adianti- 
folia) . 

Ladies' tresses (Spiranthes gracilis) . 

Yellow fringed orchis (Habenaria cili- 
aris) . 

Lady's slipper (Cypripedium acaule). 

Banana (Musa sapientum) . 

Canna (Canna hidica). 

Blue flag (Iris versicolor). 

Blue-eyed grass (Sisyrinchium angusti- 
folium) . 

Snowdrop (Galanthus nivalis). 

Carrion flower (Smilax herbacea). 

Common greenbrier (Smilax rotundi- 
folia) . 



Day lily ( Hemerocallis fulva) . 

Adam's needle ( Yucca filamentosa) . 

Lily of the valley ( Convallaria majalis) . 

Solomon's seal (Polygonatum biflorum). 

Asparagus (Asparagus officinalis). 

False Solomon's seal (Smilacina race- 
mosa) . 
* Maianthemum Canadense. 

Bell wort ( Oakesia sessilifolia) . 

Wood lily (Lilium Philadelphicum) . 

Wild yellow lily (Lilium Canadense). 

Tiger lily (Lilium tigrinum) . 

Indian cucumber root (Medeola Vir- 
ginica) . 

Pickerel weed (Pontederia cordata). 

Yellow-eyed grass (Xyrisflexuosa). 

Common cat tail (Typha latifolia). 

Bur reed (Sparganium simplex). 

Indian turnip (Ariswma triphyllum). 

Arrow arum ( Peltandra undulata) . 

Skunk cabbage (Symplocarpus fmti- 
dus). 
*Sweet flag (Acorus Calamus). 

Phyllodendron Amurense. 
*Water plantain (Alisma Plantago). 

Arrow head (Sagittaria variabilis, var. 
gracilis) . 

Cotton grass (Eriophorum p>olystach- 
yon). 

Millet ( Panicum miliaceum) . 

Finger grass (Panicum sanguinale). 
*Barnyard grass (Panicum Crus-galli). 

Herd's grass, Timothy (Phleum pra- 
tense) . 
*Meadow foxtail (Alopecurus pratensis) . 

Common oat (Arena sativa) . 

Eragrostis piectinacea. 

Low spear grass ( Poa annua) . 

Kentucky blue grass (Poa pratensis) . 

Barley (Hordeum vulgare). 

Orchard grass (Dactylis glomerata). 

Quitch grass (Agropyrum repens). 

Bamboo (Bambusa arundinacea). 

Indian corn (Zea Mays). 

Common horsetail (Equisetum arvense). 

Common brake (Pteris aquilina). 
*Spleenwort (Asplenium ebeneum). 

Shield fern (Aspidiian Noveboracense) . 

Sensitive fern (Onoclea sensibilis) . 

Flowering fern ( Osmunda regalis) . 

Osmunda Claytoniana. 

Cinnamon fern ( Osmunda cinnamomea) . 
*Ground pine (Lycopodium obscurum) . 

Selaginella apus. 



FOOD PLANTS. 



323 



Plants upon which the Gypsy Moth Caterpillar has been found feeding 

in the Field. 



Tulip tree ( Liriodendron Tulipifera). 
Barberry {Berberis vulgaris). 
Bass wood (Tilia Americana). 
European linden {Tilia Europcea). 
Northern fox grape ( Vitis Labrusca) . 
Horse chestnut {.Esculus Hippocasta- 

num). 
Sugar maple {Acer saccharinum) . 
AVhite maple {Acer dasycarpum) . 
Cut-leaved maple {Acer dasycarpum, 

var. Weirii). 
Red maple {Acer rubrum) . 
Staghorn sumach ( Rhus typhina) . 
Smooth sumach {Rhus glabra) . 
Poison ivy {Rhus toxicodendron). 
Common locust {Robinia Pseudacacia). 
Cercidiphyllum Japonicum. 
Wild red cherry {Primus Pennsijlvan- 

ica) . 
Choke cherry {Primus Virginiana). 
W ild black cherry ( Prunus serotina) . 
Damson plum {Primus domestica). 
Purple-leaved plum {Prunus Pissardi). 
Wild red raspberry {Rubus strigosus). 
Thimbleberry {Rubus occidentalis) . 
High blackberry {Rubus villosus). 
Low blackberry {Rubus Canadensis). 
Strawberry {Fragaria Virginiana). 
Rose {Rosa nitida) . 
Dwarf wild rose {Rosa lucida). 
Choke berry {Pyrus arbutifolia) . 
American mountain ash {Pyrus Amer- 
icana) . 
Pear {Pyrus communis). 
Apple {Pyrus Malus). 
Paul's thorn {Cratcegus coccinea, var. 

Paulii) . 
Shad bush {Amelanchier Canadensis). 
Quince ( Cydonia vulgaris) . 
Arrow wood ( Viburnum acerifolium) . 
Ox-eye daisy {Chrysanthemum Leu- 

eanthemum) . 
Burdock {Arctium Lappa). 
Dangleberry {Gaylussacia frondosa) . 
Low blueberry {Vaccinium vaciUans). 
Swamp blueberry {Vaccinium corym- 

bosum) . 



Clammy azalea {Rhododendron visco- 

sum). 
White ash {Fraxinus Americana). 
Common lilac {Syringa vulgaris). 
Bittersweet {Solanum Dulcamara). 
Mullein {Verbascum Thapsus). 
Slippery elm {Ulmus fulva) . 
White elm {Ulmus Americana). 
English elm {Ulmus campestris). 
Sycamore {Platanus occidentalis). 
Butternut {Juglans cinerea). 
Shell-back hickory {Carya alba). 
White-heart hickory {Caryatomentosa). 
Pignut {Carya porcina). 
Bay berry {Myrica cerifera). 
American white birch {Betula populi- 

folia) . 
Paper birch {Betula papyrifera) . 
River birch {Betula nigra) . 
Cut-leaved birch {Betula alba, var. 

laciniata) . 
Smooth alder {Alnus serrulata). 
Wild hazel nut {Corylus Americana). 
White oak {Quercus alba). 
Swamp white oak {Quercus bicolor). 
Red oak {Quercus rubra). 
Scrub oak {Quercus ilicifolia) . 
Chestnut {Castanea sativa, var. Ameri- 
cana) . 
Blue beech {Carpinus Caroliniana) . 
American beech {Fagus ferruginea) . 
Purple beech {Fagus sylvatica, var. 

purpurea) . 
White willow {Salix alba). 
Weeping willow {Salix Babylonica). 
American aspen {Populus tremuloides). 
Balm of Gilead {Populus balsamifera, 

var. candicans). 
White pine {Pi?ius Strobus). 
Pitch pine {Pinus rigida). 
Common greenbrier {Smilax rotundi 

folia) . 
False Solomon's seal {Smilacina race- 

mosa) . 
Kentucky blue grass {Poa pratensis) . 
Common brake {Pteris aquilina). 



Plants upon which the Gypsy Moth Caterpillar did not feed. 



Red baneberry {Actcea tpicata, var. 

rubra) . 
Rocket larkspur {Delphinium Aj'acis). 



Bee larkspur {Delphinium elatum). 
Great-flowered larkspur ( Delphinium 
grandiflorum) . 



324 THE GYPSY MOTH. 



Plants upon which the Gypsy Moth Caterpillar did not feed — Concluded. 



Winter cress (Barbarea vulgaris) . 
Balsamine (Impatiens balsamina) . 
Myrtle (Myrtus communis) . 
Bur cucumber (Sicyos angulatus). 
Everlasting (Antennaria plantagini- 

folia). 
Common everlasting ( Gnaphaliumpoly- 

cephalum) . 
Common mugwort(Artemisia vulgaris) . 



Blue bottle {Centaurea Cyanus). 
Rattlesnake weed (Rieracii/m venosum) . 
Indian pipe (Monotropa xmiflora). 
Red pepper (Capsicum annuum). 
Ground hemlock (Tarus Canadensis). 
Pogonia ophioglossoides. 
Ground pine (Lycopodium complana- 

tum) . 
Marsilia quadrifolia. 



Cotton as a Food Plant, 

The question was raised whether the gypsy moth would 
prove destructive to the cotton plant in the South, should it 
by any means escape from its present locality and become dis- 
tributed in the cotton States. To decide this question, cotton 
seeds were planted and two small plants were raised. When 
one of these was about two inches high, gypsy caterpillars 
were placed on it, and they devoured not only the leaves but 
nearly all the stem, during a single night. The second plant 
died before reaching the size desired for the experiment. 

By correspondence with Mr. F. B. Carpenter of the agri- 
cultural experiment station at Raleigh, N. C, a dozen small 
cotton plants were obtained, which were from two to two 
and a half feet high. Although the plants were well packed, 
they were badly wilted when they arrived. All but two were 
set out in the ground in different places, in the hope that 
some of the varied soils would prove congenial, but unfort- 
unately none of them lived. The leaves of one remaining 
plant were taken off and put into ajar with ten caterpillars. 
Notwithstanding the fact that the leaves were badly wilted, 
the caterpillars on the second day had eaten about one-fourth 
of them, but at the end of this day the leaves had become so 
dry that this experiment was discontinued. The remaining 
plant, having been kept in water, had revived somewhat, and 
on July 22 twenty caterpillars, of the fifth molt, were placed 
upon it, the base of the plant being kept in water. The cat- 
erpillars at once began feeding heartily on the plant, appear- 
ing to prefer the fresh leaves at the top to the lower wilted 
ones. They continued to feed till July 25, at which time 
they had devoured the greater part of the plant, having eaten 
leaves, tender petioles and half- developed boll. From this 




PLATE 46. Oak branch attacked by gypsy moth caterpillars, 
Saugus, July, 1894. 



EUROPEAN FOOD-PLANTS. 



325 



experiment it seems evident that, if they were numerous in 
a Southern cotton field, they might prove quite as destruc- 
tive as the cotton worm (Aletia argillacea) . 



Plants upon which the Gyp>sy Moth Caterpillar has been known to feed 

in Europe. 

Olive ( Olea Europeaa) . 
Ash ( Fraxinus excelsior) . 
Rhubarb {Rheum Rliaponticum). 



Cabbage (Brassica oleracea) . 

Rock rose ( Cistus Laurifolius) . 

Linden {Tilia Europtea). 

Spindle tree (Euonymus verrucosus). 

Sycamore {Acer Pseudo-Plantanus) . 

Tartar maple {Acer Tartaricum). 

White lupine (Lupinus albus). 

Maple {Acer platanus) and other species. 

Sainfoin (Onobrychis sativa). 

Chinese wistaria {Wistaria Sinensis). 

Pea vines {Pisum sativum). 

Honey locust {Gleditschia triacanthos) . 

Plum {Prunus domestica). 

Prune ( Prunus occidentalis ?) . 

Peach {Prunus Persica). 

Apricot {Prunus Armeniaca). 

Sloe {Prunus spinosa) . 

English cherry {Prunus Avium). 

Laurel cherry (Primus Laurocerasus) . 

Black service berry {Prunus padus) . 

White thorn ( Crat(pgus Pyracantha) . 

Hawthorn (Cratccgus Oxyacantha). 

Quince (Cydonia vulgaris). 

Mountain ash (Pyrus aucuparia). 

Apple (Pyrus malus). 

Pear (Pyrus communis). 

European medlar (Mespilus German- 

ica) . 
Chinese medlar (Photinia serrulata). 
Loquat tree (Eriobotrya Japonica) . 
Strawberry (Fragaria vesca). 
Rose (Rosa canina). 
Rose (Rosa centi folia) . 
Pomegranate (Punica granatum) . 
Currant (Ribes alpinum). 
Gooseberry (Ribes Ura-crispa). 
Cucumber (Cucumis sativus) . 
Spotted hemlock ( Conium maculatum) . 
Water hemlock (Cicuta virosa). 
Lettuce (Lactuca sativa). 
Heath (Erica Melaleuca) . 
Heather ( Calluna vulgaris) . 
Azalea, various species. 
Pimpernel (Anagallis arvensis ?) . 



Elm ( Ulmus campestris) . 

Elm ( Ulmus effusa) . 

Elm (Ulmus pedunculata) . 

Elm ( Ulmus subrosa) . 

Fig (Ficus Carica). 

Plane tree (Plata?ius orientalis). 

Walnut (Juglans nigra) . 

Cork oak ( Quercus suber) . 

Holm oak ( Quercus Ilex) . 

Winter oak ( Quercus ])edunculata, var. 
tardijlora) . 

Oak (Quercus pubescens) and other 
species. 

Chestnut (Castanea vesca) . 

Beech (Fagus sylvaticus). 

Hazel-nut (Corylus Avellana). 

Hornbeam (Carpinus betulus). 

Hornbeam ( Carpinus orientalis) . 

Sweet gale (Myrica gale). 

Birch (Betula alba) and other species. 

Alder (Alnus glutinosa). 

Speckled alder (Abuts incana). 

Osier willow (Salix vimiiialis) . 

White willow (Salix alba). 

Brittle willow (Salix frag His). 

Poplar willow (Pojntlus nigra). 

Aspen (Populus tremula). 

Willow (Popuhis alba) and other spe- 
cies. 

Fir (Pinus Abies). 

Scotch fir (Pinus sylrestris) . 

Pine (Pinus Picea) . 

Larch ( Larix Europma) . 

Spruce (Abies excelsa). 

Arbor vitas (Thuja occidentalis). 

Savin (Juniperus Sabina). 

Cypress (Cupressus sempervirens). 

Lime tree (Cupressus Limetta). 

Yew (Taxus baccata). 

Grass, various species. 

Grain. 



An Experiment in Starving Caterpillars. 
March 20, 1895, twenty-five newly hatched caterpillars, 
and also the same number from each of the first, second and 



326 



THE GYPSY MOTH. 



third molts, were placed in corked vials without food, and 
kept in a normal temperature, in order to see how long they 
would live under such conditions. Observations were made 
on them at intervals of twenty-four hours. The following 
table gives the number of caterpillars dying on the specified 
dates : — 





si in 




73 . 

Jh CO 






o . 

•f CD 

s 


"3 . 




W > 

H en 


o . 
h o 


"3 
o 

H 


Just hatched, . 


- 


- 


5 


8 


12 












25 


First molt, 


- 


- 


1 


11 


13 










25 


Second molt, . 


- 


- 


- 


7 


9 


9 


- 


- 


" 


- 25 


Third molt, . 




- 


- 


9 


7 


3 


1 


3 


- 


2 25 



This shows that caterpillars in the earlier stages will 
readily live four days without food ; that an appreciable 
number of second-molt caterpillars will live under the same 
conditions for five days, while the third-molt caterpillars 
may exist on starvation diet for nine days. 

To gain further knowledge of the period of time it is 
possible for gypsy moth caterpillars to live without food, 
a number of them were placed in cold storage, and a few 
removed from time to time and supplied with food. For 
this work, which was carried on during the month of April, 
1895, use was made of a double box packed with sawdust 
and stored in a refrigerator, the temperature of which 
averaged about 40° F. The caterpillars were kept in corked 
vials and removed as needed. At the ordinary tempera- 
ture of the refrigerator the caterpillars became rigid and 
inactive, and remained so throughout the time involved in 
the experiment. April 3, 1895, a number of caterpillars in 
each of the different molts, from those just hatched to those 
between the fourth and fifth molt inclusive, were placed, with- 
out food, in corked vials in the refrigerator box. All of 
those between the fourth and fifth molt died within a day 
or two, possibly due to contact with the large quantity of 
saliva which they ejected soon after being placed in the box. 



EFFECTS OF TEMPERATURE. 327 

At intervals of a few days several of the caterpillars of 
the different ages were removed from the refrigerator and 
placed on suitable food in a warm room ; and in this way the 
length of time the caterpillars could exist without food, was 
determined. None of the caterpillars between the third and 
fourth molt were alive when removed from the box April 6. 
Of those between the second and third molt, a single cater- 
pillar remained alive April 24, and this one, when supplied 
with lettuce leaves, revived, fed and molted at the end of 
nine days. April 12, a number of caterpillars between the 
first and second molt were removed, and when supplied with 
food revived and besran feeding. Several of the newlv 
hatched caterpillars were found to be alive April 24, and 
when supplied with food a number of them were able to feed, 
and so reached maturity, after having been deprived of food 
for a period of three weeks. 

A nearly full-grown caterpillar, confined in a box July 
30, 1894, without food, lived until August 9, but died the 
night of that day. Lodi states that a caterpillar of this moth 
in Europe went without food for twenty-seven days without 
injury ("Opuscol. scelt.," vol. XII, page 183, 1789). 

Effect of Extremes of Temperature on Caterpillars of the 

Gypsy Moth. 
Effect of Heat. — Fifty caterpillars, in lots of ten, taken 
from the different molts, from those just hatched up to and 
including the fourth molt, were exposed for fifteen minutes 
to a temperature of 110° F., and were then placed in jars 
and supplied with food. Of those just hatched, only one 
died ; of those of the first molt, three ; of the second molt, 
three ; of the third molt, three ; and of the fourth molt, 
three. The rest of the caterpillars survived and molted. 
Fifty caterpillars, selected in the same manner as those of 
the preceding experiment, were exposed to a temperature 
of 120° for a period of fifteen minutes. Of those just 
hatched, ten died; of the first molt, ten; of the second 
molt, ten ; of the third molt, nine ; and of the fourth molt, 
only one. April 4, fifty caterpillars were exposed to a tem- 
perature of 130° for a period of fifteen minutes. The cater- 
pillars used in this experiment comprised those just hatched 



328 THE GYPSY MOTH. 

and the various molts up to and including the fourth. 
When taken from the oven, all but one were dead. 

Effect of Cold. — Ten caterpillars just hatched, also ten 
from each molt up to the fourth, were selected and placed in 
vials, after which they were subjected to a temperature of 
85° for a period of five minutes. They were then placed in 
a cold box, where they were exposed to a temperature of 2° 
above zero for a period of thirty minutes, at the end of which 
time they were removed to a room where the temperature 
was 70°, and examined. Only one caterpillar survived the 
above treatment, but this one, after a few days, fed and grew 
in a normal manner. Fifty caterpillars, in lots of ten, from 
the different molts, were transferred from a normal tempera- 
ture of 70° and exposed to a temperature of zero for a period 
of half an hour, when they were returned to the tempera- 
ture from which they were first taken. When removed, all 
were dead. Fifty caterpillars in the various molts, up to 
and including the fourth, were placed in vials (the mouths 
of which were stopped with cloth instead of cork), and then 
removed from a temperature of 82° to a cold box, where 
they remained fourteen hours, exposed to an approximate 
temperature of zero. All were dead when taken out. 

A study of these experiments shows that, as a rule, the 
small caterpillars possess the ability to resist a considerable 
degree of cold but not of heat ; while the larger caterpil- 
lars possess the ability to resist the heat better than the 
cold. This is as one would naturally expect to find it, 
since at the time of hatching the weather is usually cool, 
while the increase in size of the caterpillars keeps pace 
with the ordinary increase of temperature, so that by the 
time the caterpillars are full grown we often have a con- 
siderable degree of heat. 

Experiment in drowning Caterpillars. 
In many places the gypsy moth infests the trees along the 
course of streams, under such circumstances as to lead to 
the impression that they were distributed by falling into 
the water while in the caterpillar stage, and, drifting down 
stream with the current, reached the shore, and, making 



POSITION ON TREES. 329 

their way to suitable food plants, passed their transforma- 
tions and thus established new colonies down stream. 

To determine the actual resistance of these caterpillars to 
water, the following experiments were made in July, 1895. 
July 12, four jars were filled with water, and at 9 a.m. five 
gypsy moth caterpillars of the fifth molt were placed in 
each. In jar No. 1, half of the caterpillars were alive the 
third day ; the remainder died July 17. In jar No. 2, one 
caterpillar died the first and two the second day ; the other 
two lived until the morning of the fifth day. In jar No. 3, 
one died the first and the rest the fifth day. In jar No. 
4, one died the first and one the second day, the rest living 
until the morning of the fourth day. These results show that 
the gypsy moth caterpillars are able to live in water for two or 
three days, during which time, if they should fall into swiftly 
moving streams, they would be carried a considerable dis- 
tance, and in this manner some of the colonies found along 
the shores of streams may have been established. 

Position of Caterpillars on Trees. 
To ascertain the normal position of the caterpillars of the 
gypsy moth on trees, a tight board fence was built around a 
medium-sized apple tree upon which a number of caterpillars 
were feeding. The fence was five feet in height, and en- 
closed an area of eighteen by eighteen feet. At a height of 
three feet from the ground a wide band of raupenleim was 
placed around the fence on the inside, and at the base the 
earth was banked up to the height of one foot, in order to 
prevent the escape of the caterpillars. Careful observations 
were made every morning by Mr. W. L. Tower, on the 
location of the caterpillars and the places where they had 
gone to rest after they stopped feeding. As the number of 
caterpillars on the tree was not always the same, no tabu- 
lated list of their positions could be made ; yet the relative 
number found each day, in the same place and position, was 
more constant than could be expected. By adding the num- 
ber found in each location and the number found on the tree 
every day, the percentage in each place was found to be 
fairly constant. 



330 



THE GYPSY MOTH. 



1894. 


Number 
under Burlap. 


Number 
on Trunk. 


Number 
on Branches. 


Number 
on Leaves. 


Number 
on Tree. 


July 16, . 
July 17, . 
July 18, . 
July 19, . 
July 21, . 
July 23, . 
July 25, . 


14 

30 
31 
80 
75 
100 
74 


1 

3 
2 

_* 
_ * 

7f 


12 
16 
12 
47 
38 
28 
25 


3 

7 


27 
52 
45 
134 
113 
139 
106 


Total, . 
Per cent, 
(about), . 


404 
66 


6 
1 


178 
29 


10 

2 


616 



The average per cent, of the number under the burlap did 
not vary much from sixty-six. The number found elsewhere 
on the trunk and on the leaves of the tree together did not 
constitute three per cent, of the whole. 

In the early morning, before the rays of the sun struck 
the burlap, the caterpillars were found under it on all sides 
of the tree, but as the sun rose higher, the greater part 
of them were on the west and northern sides, away from 
the heat and light. As the sun went from east to west they 
moved around the tree, keeping on the shady side. This 
was true of the larger portion of the caterpillars, but in 
some instances they have been found at mid-day resting 
under the direct rays of the sun, with no covering whatever. 
The caterpillars that were on the larger branches of the tree, 
where the sun did not strike them, remained in the same 
position all day unless disturbed, while those on the smaller 
branches moved around, keeping on the shady side nearly 
all the time. 

Spinning Habits of Caterpillars. 
The amount of silk a gypsy moth caterpillar is capable 
of spinning has an important bearing on the distribution of 
these insects, since it is known that by spinning down upon 
passing teams, etc., the caterpillars are carried from place to 
place. The more silk a caterpillar is capable of spinning, 



* Base of tree. 

f Not counted in the results, as they were pupating. 



SPINNING HABITS. 331 

the greater are its chances of being carried into new localities. 
To learn the quantity of silk that one of these caterpillars 
can spin, a reel was made and mounted in a frame. Cater- 
pillars were taken on a soft brush and then jarred off into 
space. This caused them to spin, when, by attaching the 
end of the thread to the wheel and manipulating the cater- 
pillars carefully, the silk was reeled off and a record kept of 
the number of revolutions of the wheel, until the caterpillars 
could not or would not spin. It was found that they spun 
best when a slight current of air was blown upon them. In 
this manner caterpillars of known ages were experimented 
with. Many of these experiments gave only negative results, 
for the manipulation necessary in getting the thread started 
often disturbed them so that they would spin only a few feet. 
The following results were obtained from a number of the 
experiments : — 

March 22 : Four caterpillars, just hatched, were taken be- 
fore any of their store of silk had been drawn upon. The 
first spun 4 feet and 6 inches, the second spun 9 feet and 1 
inch, the third spun 38 feet and 2 inches, and the fourth spun 
69 feet and 4 inches, — a distance greater than the height of 
an average shade tree. March 14 : Of five first-molt cater- 
pillars, the first spun 53 feet and 2 inches, the second 24 
feet and 2 inches, the third 3 feet and 2 inches, the fourth 6 
feet and 4 inches and the fifth 7 feet. 

April 23 : Three more caterpillars, of the first molt, were 
experimented with, and the following results obtained : the 
first spun 25 feet and 3 inches, the second 22 feet and 6 
inches and the third 47 feet and 9 inches. March 22 : Of 
two second-molt caterpillars, the first spun 8 feet and the 
second 2 feet. Other caterpillars, in the later molts, were 
tried, but they could not be induced to spin. There seems 
to be a decrease in spinning power as the caterpillar grows 
older. Caterpillars of the second, third and fourth molt have 
been seen spinning down to a considerable distance from trees 
on which they were feeding, and in this manner they were 
able to make the wind and passing teams aid them in finding 
their way to suitable food plants. 

The last thing before entering upon the rest previous to 
molting is the spinning of a number of threads, forming a 



332 THE GYPSY MOTH. 

small silk mat, a little longer in diameter than the length of 
the body of the caterpillar. When rocks have been burned 
over, caterpillars have been seen spinning down to escape the 
smoke and heat. They frequently spin threads from fences 
to the neighboring trees. The insect also spins a scanty 
cocoon for a shelter and support during the pupal stage. 

The Process of Pupation. 
Cocoon. — When the caterpillar is fully grown, it seeks 
some sheltered spot (Plates 47, 49), and rests quietly for 
about twenty-four hours. It then empties its alimentary 
canal,* the discharge being of a semi-fluid nature, and con- 
taining an abundance of chlorophyl, showing it to be, in 
part at least, the remains of food. In about one hour after 
this discharge, the caterpillar begins to spin a frail cocoon, 
which is composed of a few coarse brown silken threads, 
occasionally enclosing a leaf or other material. In spinning, 
it first places its spinneret close to the surface on which the 
cocoon is to be formed, and presses out a drop of the silk- 
forming fluid, which serves as an anchor for the silk thread 
which is then spun out. It first spins a few long threads, 
which usually exceed the length of the cocoon when finished. 
After a number of these long threads, which connect various 
points and serve as a sort of frame, have been formed, the 
caterpillar begins to spin more rapidly, and to place short 
threads between the long ones, working always from the 
inside, and changing at intervals from one side of the cocoon 
to the other. Where the threads cross each other they are 
fastened together by a drop of the fluid in much the same 
manner as at the starting of the cocoon. In spinning, the 
labial palpi and the feet are used to grasp the threads. As 
a rule, the spinning is not completed at a single operation, 
since the caterpillar rests several times, the rests ranging 
from a few minutes to five or six hours. The actual time 
spent in spinning is about six hours. After completing its 
network of silk the caterpillar rests quietly, except for occa- 
sional spasmodic twitchings of the body, hanging head down- 
ward, and pupates at the end of about three hours. 

Pupation. — When the process of pupation begins, the 
skin commences to contract and wrinkle on the posterior 










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jg ^,.'~ 








km 












^8» 






* 


ffpi 






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. • 


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* 



PLATE 47. Mass of pupse between the trunks of two trees. From a 
photograph taken at the Winning colony, Woburn, July, 1895. 




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fMj/ 


W #" 


■^j4 








A 




Explanation of Plate 48. 

[All figures enlarged.] 



Drawn by R. A. Coolev. 



Ventral view of male pupa. 

Ventral view of female pupa. 

Dorsal view of female pupa. 

Lateral view of female pupa. 

Genital markings of male pupa. 

Genital markings of female pupa. 

Chitinized hook from cremaster of pupa, 
greatly enlarged. 

Aerostatic hair from newly hatched cater- 
pillar, greatly enlarged. 

Normal hair from caterpillar, greatly enlarged. 



THE PUPA. 333 

segments of the caterpillar, showing that the pupa is being 
withdrawn from that part. The pupa is pushed forward 
by a vigorous use of the cremaster. In this manner the 
skin on the posterior segments is pushed back, and the 
pressure on the anterior segments becomes so great as to 
nearly bend under that part of the body. The insect takes 
short rests at intervals during this process. Next, the skin 
on the fourth segment splits along the dorsal line, the split 
continuing forward and backward, and in a few seconds 
extends from the base of the head to the annulation between 
the fourth and fifth segments, the pupa, in the mean time, 
forcing itself outward against the opening thus made. In a 
few seconds more the movements of the pupa, aided by the 
pressure from behind, which it is able to exert by means 
of its cremaster, splits the head down on each side of the 
clypeus to the mouth parts, and the pupa emerges by pass- 
ing outward through the opening, the whole process taking 
about fifteen minutes. 

The newly formed pupa is very soft and of a light color, 
with the remains of the larval tubercles and markings 
plainly visible, but these disappear and the pupa grows 
harder and darker when exposed to the air. Caterpillars, 
in their attempts to pupate, sometimes burst the thin pupal 
skin and die from the escape of the fluids from the body. 
In changing from the larval to the pupal stage, the insect 
loses about thirty-five per cent, in size and nearly forty-five 
per cent, in weight. A small part of the weight is left in 
the larval skin and silk. How the insect, as a rule, fastens 
itself to the silk in which it is enclosed, is not fully known. 
In one case, however, a pupa was seen to emerge and fall 
into the network of silk, when, by a wriggling motion, it 
picked up the silk threads on its cremaster and then hung, 
from gravity, head downward. 

The maximum time spent in the pupal stage by one 
hundred females was found to be 14 days, the minimum 7 
and the average 10.65. The maximum time spent in the 
pupal stage by eighty-eight males was found to be 17 days, 
the minimum 9 and the average 13.41 days. 

Pupa (Plate I, Fig. 5, and Plate 48).— The pupa? of the 
males vary in length from three-fifths to four-fifths of an inch, 



334 THE GYPSY MOTH. 

including the cremaster, or blunt spine at the end of the 
abdomen, while those of the females vary from three-fifths to 
one and two-fifths inches. Fig. 5, Plate I, was taken from 
one of extraordinary size. The following description was 
made from the study of thirty-nine males and one hundred 
and twenty-one females : — 

They vary in color from chocolate to dark reddish-brown, 
and are cylindrical or fusiform, rounded anteriorly and taper- 
ino- posteriorly to the cremaster, which is armed at the tip 
with a cluster of minute hooks, one of which is shown at 
Fi°\ 7, greatly enlarged. The covers to the various parts 
of the body, as the wings, legs, antennas, etc., are plainly 
marked ; those of the wings are quite broad, and reach to 
the posterior third of the fifth segment, while those of the 
antennte are strongly curved, being much wider in the 
males than in the females. At the front edge of the meso- 
thorax, on each side, is an oval, dark reddish-brown velvety 
spot, very distinct in some examples but nearly invisible in 
others. Ochre-yellow hairs, arranged in groups, occur on 
the eye, head and palpi covers, across the collar and thorax, 
and in eight equidistant rows along the abdominal segments. 
Some of the hairs in the groups across the collar and thorax 
are dark brown. The abdominal segments are more or less 
punctured, and the hairs arise in small circles. At the base 
of the cremaster, on the ventral side, is an elliptical depres- 
sion, with curved ridges on each side. In the males, on the 
middle of this segment, in front of the depression, is a small 
raised tubercle, with a longitudinal slit on the top of it 
(Fig. 5), while in the females this tubercle is wanting; on 
the extreme front edge of this same segment, however, there 
is a fine longitudinal slit, but the surface at this place is not 
raised (Fig. 6). 

Attached Pupce. — In order to determine the best plan for 
raising the finest specimens of gypsy moths, a number of 
experiments were made in the laboratory. In six of the ex- 
periments the pupae were fastened to the bottom of a small 
pasteboard box, in which they were confined by means of a 
pin put through the little bunch of silk at the end of the cre- 
master, and then into the bottom of the box. The moths all 
emerged from these pupse, and were in good condition. In 



PUPATION. 335 

two experiments a very fine pin was run through the cre- 
master, as near to the end as possible ; but it was found that 
the pin injured the pupae, and consequently they died without 
emerging. A very fine pin was run through the last seg- 
ment of a pupa, which began to emerge, but died, being 
unable to complete the process. In several other cases pupre 
were stuck to the bottom of the box by means of a drop of 
mucilage or a drop of sticky fly-paper gum. This was un- 
satisfactory, however, for the pupa?, in wriggling about, got 
themselves covered with the gum, and the few which did 
emerge were in very poor condition. 

Mass of Pupce. — When about to pupate, the caterpillars, 
when numerous, collect in masses to spin their cocoons. On 
the flat side of a rock one of these masses (Plate 49) was 
found which measured eighteen inches in length and eight 
inches in width, the whole being covered by one large net- 
work of silk. Beneath two partly eaten leaves of oak forty- 
nine caterpillars had pupated, and another mass was found 
in a groove between the trunks of two small trees (Plate 
47), containing at least three hundred pupa? and pupa-cases. 

Pupation in the Field. 

To learn the proportion of caterpillars which pupate on 
trees and on the ground, as well as the per cent, of those 
parasitized, a study was made of the " Winning " colony at 
Woburn, in the latter part of July, 1895, the results of 
which show that the larger part of the caterpillars pupated 
in the trees. On the border of the colony, about forty per 
cent, pupated above the burlap ; while in the centre, about 
sixty per cent, were found to have pupated above it. These 
facts confirm the generally accepted opinion that, when very 
abundant, the per cent, of caterpillars pupating upon the 
trees is somewhat increased. 

Of the caterpillars which pupated elsewhere in the col- 
ony, the proportion was equally divided between those that 
pupated on the ground and those which passed the pupal 
stage on the trunks and under the burlaps on the trees. 
All pupse which gave evidence of parasites, as well as the 
empty pupa-cases from which parasites had apparently 
emerged, were counted as parasitized. The per cent, of the 



336 THE GYPSY MOTH. 

sexes found to be parasitized was 9.7 per cent, of the males 
and 7.5 per cent, of the females. This does not agree with 
observations previously made, where the larger per cent, 
parasitized were found to be females. The greater part of 
the parasitized pupae were brought in, and many were found 
to contain Dipterous larvae. In most cases no parasite ima- 
goes were obtained from these pupae, although some of the 
Dipterous maggots have not yet transformed.. 

The Imago. 
The Process of Emerging. 
The emerging of the imago from the pupa is accom- 
plished as follows : when the insect is fully developed and 
ready to come forth, it forces off the cap on the anterior 
ventral part of the pupa, comprising the antennae, head and 
leg shields, and through the opening thus formed the antennae 
appear, and then the first two pairs of legs are drawn out. 
The cap is attached to the rest of the pupa at its apex, and 
its larger anterior end is pushed away from the body by 
means of the feet. The legs at first are stiff at the joints 
between the tibiae and tarsi. Next, the juncture of the wing 
covers on the top of the back splits, then the posterior 
margin of the wing covers comes off, and the insect crawls 
up and out of the pupa-case, the hind legs coming out at the 
same time as the wings. This process requires from five 
minutes to five hours, according to the resistance of the pupa- 
case and the vigor of the enclosed imago. When the moth 
first emerges it is quite moist, but soon dries off. From 
twenty minutes to two hours are required for the develop- 
ment of the wings. 



'a- 



Description of the Imago. 
The following description was made from thirty males and 
thirty-seven females. The males (Plate I, Fig. 3) measure 
from 37 to 50 mm. (one and one-half to two inches) be- 
tween the tips of the expanded wings. The ground color 
of all the wings is brownish yellow, varying in intensity in 
different examples, but somewhat lighter beneath. The 
head, thorax, antennae and upper side of the palpi are 



THE IMAGO. 337 

grayish brown, inclining to mouse color in some specimens. 
The under side of the entire body, legs and palpi is some- 
what lighter than the under side of the wings. 

The markings on the fore wings are dark brown, and are 
as follows : the half line starts from the costa, near the base 
of the wing, and extends half way across the wing. The 
transverse anterior line arises from the basal fourth of the 
costa and crosses the wing as a scalloped line. Just outside 
of this line, on the cell, is the small orbicular spot. The 
reniform spot is crescent shaped, and, resting on the outer 
end of the cell, extends across its entire width. The median 
shade is quite obscure, but is bent out around the end of the 
cell, and toothed along the outside. The transverse poste- 
rior line arises from the outer fourth of the costa, is some- 
what curved and toothed on the veins, and terminates just 
within the anal angle. The subterminal line, a little outside, 
is similar to the transverse posterior line and parallel with 
it. The terminal space is usually somewhat darker than the 
rest of the wing, and all the cross lines are heavier on the 
costa than elsewhere. The fringe is cut with dark brown 
between the veins. 

The hind wings have a faint discal lunule at the end of the 
cell, and the terminal shade is darker brown than the rest of 
the wing. The upper side of the abdomen is of the same 
color as the upper side of the hind wings, and has a row of 
brownish spots along the middle. 

The outside of the third and fourth joints of the tarsi and 
the ends of the femora on the upper side are brown ; the fore 
and middle tibias are pale mouse colored on the outside. 

The females (Plate I, Fig. 1) measure from 37 to 62 mm. 
(one and one-half to two and one-half inches) between the 
tips of the expanded wings. The entire body and wings 
above and beneath are yellowish white, except the abdomen 
beneath and towards the end above, which is pale yellow. 
The markings of the fore wings are dark brown or nearly 
black, but vary much in intensity in different specimens, 
being almost entirely obliterated in some examples. The 
half line at the base of the wing, the orbicular and reniform 
spots, the costal end of the transverse lines and the black 
spots in the cilia are quite pronounced. The form and 



338 



THE GYPSY MOTH. 



position of the lines and spots are the same as in the males. 
The fore wings are longer, narrower and more pointed than 
in the males. The hind wings have a faint discal spot and 
a subterminal line which is toothed along the outside on the 
veins, and the cilia have black basal spots between the veins. 
The antennae and legs are dark brown, but the hair on the 
femora and tibiae is yellowish white. 

The imago is subject to considerable variation in size. 
The following table gives the dimensions of the largest and 
the smallest imagoes of each sex, taken in the field : — 





Expanse 
of Pore 
Wings. 


Expanse 
of Hind 
Wings. 


Length 

of 
Body. 


Diameter 

of 
Thorax. 


Diameter 

of 
Abdomen. 




mm. 


mm. 


mm. 


mm. 


mm. 


Largest male, 


46 


37 


18 


5 


3 


Smallest male, 


33 


25 


12 


4 


2 


Largest female, 


71 


53 


31 


8 


12 


Smallest female, 


44 


34 


16 


5 


6 



Mr. J. H. Leech, in the "Proceedings of the Zoologi- 
cal Society of London," Vol. LVI, page 630, expresses the 
opinion that the Japanese gypsy moths, which have been 
described as distinct species, do not differ from those of 
Europe, except in size, and he regards them only as forms, 
and not distinct species. He gives the extremes of size of 
males and females in Japan and Corea as follows: "Ex- 
panse of wings of largest male, 71 mm. ; smallest male, 
37 mm. ; largest female, 114 mm. ; smallest female, 48 
mm." Mr. Leech also gives the size of European examples 
of the gypsy moth as follows: "Largest male, 54 mm.; 
smallest male, 32 mm. ; largest female, 93 mm. ; smallest 
female, 42 mm." I have in my collection three males from 
Pekin, China, which measure 46, 50 and 54 mm., respec- 
tively, in expanse of wings ; and several male examples 
from Europe, the largest of which measures 43 mm. and 
the smallest 37 mm. I can see no difference between the 
examples from China and those from Europe, except in 



size. 



Explanation of Plate 50. 

[AH fignrea greatly enlarged.] 



Drawn by C. P. Lounsbury. 



i. Dorsal view of male moth. 

2. Lateral view of genitalia. 

3. Ventral view of genitalia. 

4. Antenna of the male. 

5. Single filament from antenna. 

6. Section of antennal filament, showing insertion 

of the finer lateral filaments. 



HERMAPHRODITES. 339 



Hermaph rodites . 

Three specimens of the gypsy moth were taken in Med- 
ford, Mass., which are what Ochsenheimer would call perfect 
hermaphrodites. One has the right half of the body, with 
the wings and antenna of that side, of the form, color and 
markings of the female ; while the left side of the body, with 
its wings and antenna, is male. The second specimen is 
male on the right side, and female on the left. In both of 
these examples the frenulum is single on the male side, but 
divided on the female. In the third specimen, the antenna 
and both wings, on the left side, are female, while on the 
right side, the antenna and both wings are male. The 
abdomen is female in size and form, but the right side is 
darker than the left, looking more like the male in color. 

As the sexes of this moth differ so much in the form and 
color of the wings and in the pectinations of the antennae, 
an hermaphrodite is a remarkable insect in appearance, and 
seems almost to suggest that it is a work of art. Hermaph- 
roditism in this species is occasionally met with in Europe, 
several cases being on record in the European journals. 

External Anatomy of the Moth. 
The head is rather small, and joined by a very short neck 
to the comparatively large thorax. This is followed by the 
abdomen, which, in the male (Plate 50, Fig. 1), is medium 
in size, gradually tapering to the last two segments. These 
taper more rapidly to the genitalia or external genital or- 
gans, which consist of a genital hook and pair of clasps 
(Plate 50, Figs. 2 and 3). The abdomen of the female is 
enormously distended. The front is smooth and very slightly 
rounded ; the maxilla? or sucking tube is rudimentary ; the 
palpi small, extended forward horizontally (Plate 51, Fig. 
1 «), the basal and terminal joints being about equal in 
length, while the middle joint is about three times as long 
as either of the others, and covered with fine hairs loosely 
arranged over the surface, similar to those that cover the 
surface of the head. There are no ocelli present. The 
antenna? are bipectinated very strongly in the male (Plate 
50, Fig. 4), while in the female the pectinations are very 



340 THE GYPSY MOTH. 

much shorter and stouter (Plate 51, Fig. 3). The pectina- 
tions of the male antennae (Plate 50, Fig. 5) are somewhat 
curved, and taper slightly toward the outer end, where they 
terminate in a tooth on one side and a much longer spine 
on the other; there are numerous hairs, about twice as 
long as the diameter of the pectinations, scattered over the 
surface. Plate 50, Fig. 6, shows a portion of a pectination, 
with the bases of four of these hairs, and still finer hairs, 
scattered over the surface, which is thrown into very minute, 
irregular longitudinal ridges, visible only under a high power 
ot the microscope. The female antennae (Plate 51, Fig. 3) 
have minute, elongated, tooth-like scales and bristle-like 
hairs over the surface (Plate 51, Fig. 4), and the pecti- 
nations are cylindrical, stout and terminate obliquely in a 
point at the outer end, near which, on the lower side, is a 
short bristle. There are minute hairs sparsely scattered over 
the surface, as shown in Plate 51, Fig. 4 b, and scattered be- 
tween these are minute pits, around the edge of which is a 
row of minute hairs (Plate 51, Fig. 4 a). 

The legs (Plate 51, Figs. 5, 6 and 7) are moderately 
long and of medium size, with the first or coxal segment 
somewhat conical in form ; the second segment (trochan- 
ter) much smaller, its length being about equal to the 
thickness; the third and fourth segments (femur and tibia) 
are of nearly equal length. The outer part of the leg (tar- 
sus) consists of five segments, the first of which is about the 
length of the three following, and the last has a pair of di- 
verging claws at the end, with a fleshy organ (pulvillus) be- 
tween them (Plate 51, Figs. 9 and 10). The claws have a 
somewhat flattened under surface, with a row of small blunt 
teeth along each side. The fore legs (Plate 51, Fig. 5) have 
a long sinuous spur (tibial epiphysis) attached to the tibia 
near the base and extending a little beyond the end. The 
whole side of this epiphysis next to the tibia is covered with 
fine bristles, forming a brush-like organ. The tibiae of the 
middle legs have a pair of unequal spurs at the end, and the 
hind tibiae have a similar pair at the end and a pair about one- 
fourth of the length of the tibia above. All these spurs have 
the outer part obliquely flattened, with a row of short, blunt 



Explanation of Plate 51. 

[All figures greatly enlarged.] 



Drawn by C. P. Lounsbury. 



Lateral view of the anterior part of body 

of female. 
Ventral view of female genitalia. 
Antenna of the female. 
Section of antenna, showing sensory pits. 
Fore leg. 
Middle leg. 
Hind leg. 

Part of hind leg, with abnormal appendage. 
Foot, seen from below. 
Foot, seen from the side. 










/ ^N. 




"V — \ ' ' vC? 55 ? S! ^\ 




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w 




—^\ '^ w \1 


2 


10 







EXTERNAL ANATOMY. 341 

teeth around the edge of the flattened surface (Plate 51, 
Figs. 6 and 7). On one of the hind legs of the male, at the 
end of the tibia, was found an additional appendage on the 
side opposite to the spurs (Plate 51, Fig. 8). This is the 
only monstrosity we have thus far seen in the gypsy moth. 

The wings differ somewhat in form in the two sexes, the 
fore wings of the female being longer and more pointed 
than those of the male. The venation is shown in Plate 52, 
Figs. 1 and 2 (male), 3 and 4 (female). The frenulum at 
the base of the hind wing of the male consists of a single 
pointed bristle, while in the female it is composed of a clus- 
ter of much finer pointed bristles (Fig. 4). The surface of 
the wings is sparsely covered with scales and hairs (Fig. 7), 
and around the outer border of both the fore and hind wino-s, 
at quite equal distances apart, is a row of blunt spines, two 
of which are shown in Fig. 8, and one still more enlarged 
is represented in Fig. 9. These spines appear to be hol- 
low, with a fine aperture at the outer end. Near the hinder 
margin, towards the base of the fore wing, is an oval area 
(Plate 52, Fig. 5), the surface of which is covered with 
minute stout spines (Fig. G). The lateral surface of the 
metascutum (Plate 51, Fig. 1 g) is covered with a similar 
series of spines. 

In the "Berliner Entomologische Zeitschrift," Vol. 
XXXI, 1887, Dr. W. Donitz describes a singing Lepi- 
dopteron. After referring to the list of Lepidoptera which 
produce sounds, given by Swinton in his work on "Insect 
Variety," he describes an apparatus which he discovered in 
Dionych&pus niveus Men., a Bombycid moth found in Japan, 
and also in Siberia. He states that when a fresh male is held 
in such a manner that the wings can be moved back and forth 
on each other, one can hear a slight chirping sound, which 
continues as long as the wings are moved. He figured and 
described an apparatus, on the basal part of the fore wings, 
similar to that described above ; and a corresponding area on 
the hind wings, where that of the fore wings overlies this 
organ on the hind wings. In the gypsy moth no such organ 
exists on the hind wing, but its counterpart is found on^the 
side of the metathorax, as stated above, where the oro-an in 



342 THE GYPSY MOTH. 

the fore wings, when closed, rests on the side of the thorax. 
A similar organ occurs in Ocneria rubea of Europe, of the 
same structure and in the same place as in the gypsy moth. 

The scales on the wings vary in form, as shown in Plate 
52, Figs. 10-20. The striations are not shown in all these 
figures. Fig. 15 represents one of the short and broad 
scales with the longitudinal stride. Figs. 21 and 22 repre- 
sent cross-sections of a scale, the first from near the base, 
the second from the broader part of the scale. After suitable 
preparation and embedding inparaffine, a portion of the wing 
was sectioned and these figures drawn from the mounted 
sections. The surface of the scale next the membrane of 
the wing is smooth, while the outer surface is covered with 
longitudinal ridges. 

The abdomen of the female (Plate 51, Fig. 1) is very 
large, and densely clothed with yellowish hairs, especially 
on the under side towards the posterior part. One of these 
hairs is represented in Plate 52, Fig. 19, and a section of 
it, near the basal fourth of the hair, greatly enlarged at 
Fig. 10. The surface is covered with minute spines, which 
incline towards the apex, and it also appears to be marked 
with irregular cross-wrinkles. The ovipositor of the female 
is shown in Plate 51, Fig. 2. 

Mating. 

After emerging the female crawls a short distance from 
the pupa-case, and, by the time the wings have expanded, 
and sometimes before, she begins to attract or "assemble" 
the imagoes of the opposite sex. In colonies where the 
males are abundant, they often attempt to mate with females 
almost as soon as the latter emerge. Seeking the female, the 
male flies in a zigzag course until she is found, when he 
hovers around her for a few minutes, rapidly vibrating his 
wings. 

The time spent in mating has been found to vary from 
twenty-five minutes to three hours and eighteen minutes ; 
the average time of twenty-four pairs being one hour and 
nine minutes. After mating, the male is quite stupid, but 
in about half an hour regains his normal activity. 



Explanation of Plate 52. 

[All figures enlarged.] 



Drawn by R. A. Cooley. 



Venation of fore wing of male. 



" " hind " " " 

" " fore wing of female. 

" " hind " " " 

Base of fore wing, showing outline of the spiny area. 
Portion of the spiny area, showing the spines, greatly en- 
larged. 

7. Area from near the middle of the upper side of the fore 

wing of female, showing scales and hairs. 

8. External outer border of wing, showing spines and a fringe 

scale. 

9. Single blunt spine from outer border. 

10. Section of figure 19 greatly enlarged, showing spiny sur- 

face. 

11, 12, 13, 14, 16. Various types of scales from the wings. 
15. Scale from the upper side of the fore wing of the female, 

showing the striae. 
17, 18. Scales from the fringe of the fore wing. 

19. Hair from the end of the abdomen of the female. 

20. " " " " " " * male. 

21. Section of a scale near the base. 

22. " " " " " middle. 



Jf-Lj .£}. i Hi Oki. 




POLYGAMY. 343 

Fertilization Experiment. 

To determine the length of time necessary for fertilization, 
twenty-five virgin females were exposed in infested localities. 
After mating had commenced, the males were removed at 
the end of given periods of time, varying from one minute 
to one hour ; the females were placed in boxes, and allowed 
to deposit their eggs. 

In all cases where the male was removed before six 
minutes, the eggs proved infertile; but where they were 
allowed to remain beyond that time, the eggs were fertile. 

Polygamy . 

As a rule, the males of this species mate with but one 
female, or with two at the most, but instances have been 
recorded where single males mated with six females, and 
five other males mated with three females each. Polygamy 
is exceptional among the females. In August, 1894, a 
female moth, at the insectary, mated with three males ; but 
nearly all females reared in confinement, as well as those 
whose mating has been observed in the field, paired with 
but a single male. 

The fact that a male imago may fertilize several females 
has a practical bearing on the work of destroying the gypsy 
moth. It would seem to indicate that the destruction of the 
males, either through natural or artificial agencies, is of but 
little importance. 

Length of Life of Imago. 

The maximum number of days of the life of thirty-four 
females which had not mated was found to be 10, the mini- 
mum 1, and the average 6.15 days. The maximum number 
of days of the life of forty-two females which mated was 
found to be 12, the minimum 1, and the average 7.69 days. 
The actual length of life of the male moth is hard to deter- 
mine, as they probably live much longer when free than when 
kept in confinement. Five males which had not mated lived 
respectively 6, 7, 8, 11 and 8 days. 



344 THE GYPSY MOTH. 

Habits of Flight. 

The gypsy moth is not nocturnal, and, unless disturbed, 
but few of the males fly before 9 a.m. The time of greatest 
activity is between 10 a.m. and 3 or 4 p.m., after which time 
they seldom fly voluntarily. As already stated, they fly 
most vigorously on warm days, and in a zigzag course. 

The female moth has never been seen to fly in this coun- 
try, except on one occasion, and that was after the laying 
of the eggs. Mr. F. H. Mosher, one of our most reliable 
observers, while making observations in a colony of the 
gypsy moth in the forest at Woburn, Mass., July 18, 1895, 
saw a female gypsy moth that had finished or nearly finished 
laying her egga, upon being disturbed by males, drop to the 
ground and fly about twenty feet, striking the ground and 
rising again at distances of about two feet. In Europe, C. 
Wingelmuller, in the " Wiener Illustrirte Garten-Zeitung," 
Jan. 15, 1890, page 269, says that ''the female gypsy moth 
does not shake off her sluggishness even during- the night, 
the especial time of her activity ; and a short, lazy flight 
from one tree to another close by is the most that she accom- 
plishes." This helplessness is only on account of her body 
being stored with eggs, which prevents her from taking a 
longer flight. I have tried, again and again, at various 
times during the day, to oblige the females to fly, by throw- 
ing them into the air and also by knocking them off from the 
trees ; and in every case they only fluttered to the ground 
without any attempt to move forward by using their wings. 
On July 14, 1889, I was in the zoological gardens in Berlin, 
and saw the gypsy moths in great abundance. They were 
then in the imago stage, and occasionally females fluttered 
down from the trees in precisely the same manner that they 
do in this country when disturbed by the males. As our 
employees have observed the habits of this insect at all hours 
of the day and night, and have seen no real flight except in 
the case above mentioned, and as the statement of Wingel- 
muller seems a little indefinite, I am inclined to think that 
the female gypsy moth never voluntarily flies, nor indeed 
can she do so before laying her eggs, because of the enor- 
mous weight she would have to sustain. It may further be 



ASSEMBLING. 345 

said that, although the wings of the female are of fair size, 
they are not nearly as firm as those of the male, and it 
would seem that by disuse they have become weakened; 
and, if the present conditions are continued sufficiently long,' 
the wings of the female gypsy moth may suffer the same fate 
as those of the female of the white-marked Tussock moth 
(Plate 39, Fig. 18). 

The peculiar zigzag flight of the male may be the result 
of natural selection. As the female does not fly, the male is 
guided to her by the odor which she gives off, and which is 
disseminated by currents of air; and it is evident that males 
flying in a straight line would not meet with the scent-laden 
currents in as many cases as those which fly in a zigzag 
course. It is therefore probable that more of those having 
a tendency to an irregular course in flight would find and 
mate with the females, and thus transmit to their male 
offspring a like tendency to this particular flight, which, in 
the course of generations, has become a fixed characteristic 
of this species. 

The Assembling of the Gypsy Moth. 
It is a well-known fact that unfertilized females of the 
gypsy moth are able to attract the males to them from a 
greater or less distance. This is called assembling, and this 
power to assemble is possessed by quite a large number of 
moths more or less nearly related to the gypsy moth. 

As has been previously stated, the caterpillars ' of this 
insect have the habit of spinning down, or suspending them- 
selves from the trees on which they feed, especially when 
disturbed; and they frequently fall upon passing teams or 
animals, and are carried by them to places more or less 
remote. If, in any such case, caterpillars should be carried 
into an uninfested region, and, making their way to suitable 
food plants, should, in transforming, give rise to female 
moths, there would be little or no danger of their establish- 
ing a new colony, unless they should attract male moths 
from the infested region, and, having mated with them, 
should therefore lay fertile ego-s. 

The following experiments were made by Mr. A. H Kirk- 
land, assisted by Mr. J. P. Hylan, for the purpose of deter- 



346 THE GYPSY MOTH. 

mining, as fully as possible, how far the males might be 
assembled by the females. The question to be solved was, 
from how great a distance can a male moth recognize and 
follow up the scent of the female ? There are many condi- 
tions affecting the distance over which assembling may be 
possible. The following are a few of the more important : — 

1. The place in which the female emerges. If this occurs 
in a stone wall or rubbish heap, or in a hollow tree, the odor 
could not possibly escape and be diffused as fully as if the 
moth were exposed to the air on the outside of the tree, and 
at some height from the ground. 

2. The condition of either the male or female after emerg- 
ing. If the female is strong and in perfect condition, she 
will assemble more males than a female partly denuded. If 
the male is strong and active, he will, of course, be superior 
in flight and action to one partially crippled or enfeebled. 

3. The direction and velocity of the wind. The wind 
must blow from the place where the female emerges toward 
some place where male moths occur. A wind of high velocity 
will carry the odors farther than a light breeze, but, at the 
same time, offer greater resistance to the flight of the male 
while following up the scent. 

4. Weather and temperature. The flight of the males 
is more vigorous on bright, warm days than when the air is 
cold and damp. 

5. The contour of the land and whether it is wooded or 
not, thus forming wind-breaks. If there are forests or hills 
between the female in question and the males to be attracted, 
they will interfere with the direct passage of currents of air 
carrying the odor, so that males may fail to be attracted 
from much shorter distances than if in a region without these 
obstructions. 

Details of the Experiments. 

A level area on the salt marsh between Edgeworth and 
Somerville, entirely free from obstructions, was selected for 
the scene of operations, and stations were established from 
day to day, according to the direction of the wind. 

Stations. — The first station chosen in each experiment 
was the one where one or more females were to be located, 



ASSEMBLING. 347 

and this was always on the windward side of the marsh. 
The females were enclosed in a moth trap (Plate 54), 
which was painted on the outside with a mixture of castor 
oil and resin, and placed a few feet above the ground. The 
second station was established directly to leeward of the 
first, and at a measured distance from it. In many cases a 
third and even a fourth station was established at a known 
distance from the first and other intervening stations. It 
was often found necessary to establish three or even more 
stations, a short distance apart, on the arc of a circle, the 
radius of which was a known distance from the trap, to 
compensate for the veering of the wind, which sometimes 
carried the scent of the female out of a direct line to the 
stations first established. 

Marking the Males. — In order to carry on this work and 
obtain results at all satisfactory, it was necessary to adopt 
some s} r stem of marking the males which were to be liber- 
ated, in such a way as to enable one not only to recognize 
them afterwards, but also to determine from what station 
they came. At first they were marked by cutting a small 
notch in a certain part of the margin of the wing, with fine 
scissors. This method, while not apparently injuring them 
in any way, was objectionable, because of its being a muti- 
lation which might affect the results more or less, and 
therefore it was abandoned in the later experiments, and 
water-colors were used. It was found impossible to make 
the colors adhere to the wings, when mixed in water ; but 
fifty per cent, alcohol was found to mix well with dry car- 
mine colors, and, when applied to the wing, made a tolerably 
permanent mark. There was no difference in the results 
obtained from moths marked in the two ways. In marking, 
the color was applied, by means of a soft brush, to a par- 
ticular spot on the wings, a different mark being used for 
each station, and a different set of marks each day. The 
male moths were marked and boxed each morning, the 
marks recorded, and the moths taken into the field. The 
females were enclosed in the cage of the trap at station No. 
1, and the males were liberated at the other stations accord- 
ing to their marks. In this way it was possible, when a 
male was taken at station No. 1, to determine from which 



348 THE GYPSY MOTH. 

of the other stations it came, and the direct distance from 
that station. The negative results in so many of the experi- 
ments were not due to lack of care or attention to details, 
but in some cases to a change of wind immediately after the 
liberation of the males, and in others to a dying out of the 
wind before the males had reached the females. Many of 
the male moths, as is common with them when handled, 
would drop to the ground and remain in the grass for a long 
time ; and it was found necessary to liberate a number of 
them at each station, in order to increase the chance of meet- 
ing with the scent from the female. The following experi- 
ments were made in July, 1895 : — 

Experiment No. 1. 
"Weather, fair and clear. Wind, north-west ; average 
movement, 12 miles. Two traps, containing seven female 
moths each, were set up at 9.15 a.m., at station No. 1. At 
station 2, one-fourth of a mile to leeward of the first station, 
eight marked male moths were liberated at 9.25 a.m. At 
station 3, one-half a mile to leeward of No. 1, seven marked 
male moths were liberated at 9.35 a.m. Nothing resulted 
from this experiment. 

Experiment JS/b. 2. 
Weather, fair. Wind, at 6.10 a.m., west; from 10 a.m. 
to 3 p.m., east; average movement, 10 miles. Two traps, 
containing six female moths each, were set up at 10 a.m., 
ten feet from the ground. At station 2, one hundred and 
fifty yards to leeward, nine marked male moths were liber- 
ated at 10.15 a.m. At station 3, half a mile to the leeward 
of station 1, nine marked male moths were liberated. Four 
males were seen flying about station 1, but only one was 
captured, and this one was from station No. 3, half a mile 
distant. 

Experiment JSfo. 3. 

Cloudy. Wind, south-west to west ; average movement, 
10 miles. Two traps, containing six female moths each, 
were set up at station 1. Seven marked male moths were 
let loose at 8.10 a.m. from station 2, two hundred yards to 
leeward of the first station, and at 8.20 a.m. seven marked 



ASSEMBLING. 349 

males were liberated from station 3, half a mile to leeward 
from station 1. No males reached the first station, but the 
rain which fell from 11 a.m. till night may have prevented 
the males from flying. 

Experiment JVb. 4. 
Weather, fair. Wind, north to east ; average movement, 
10 miles. Two traps, containing six females each, were set 
up at 10.30 a.m. Forty marked males were liberated at 
10.45 a.m. from station 2, one-fourth of a mile from the first 
station, and thirty-eight marked males were liberated at 
10.55 a.m. from station 3, one-half a mile from the first sta- 
tion. At 3.30 p.m. one male moth appeared in the vicinity 
of the first station. An attempt to capture it was unsuccess- 
ful. In all probability it came from either station 2 or 3, 
since there were no infested areas in the direction toward 
which the wind was blowing. 

Experiment JSfo. 5. 
Cloudy. Wind, east ; average movement, 9 miles. Two 
traps, containing six female moths each, were set up at 8 
a.m. Nine marked males were liberated at 8.30 a.m., one- 
fourth of a mile to leeward of the first station, and nine 
marked males were liberated at 9 a.m., half a mile to lee- 
ward of station 1. None of these males reached station 1. 

Experiment JSfo. 6. 
Damp and cloudy, with light rains at intervals until 2 p.m. 
Wind, north-east ; average movement, 6 miles. One trap, 
containing a single female moth, was set up at 1.45 p.m. 
Six marked males were liberated at 2.10 p.m., 427 yards 
to leeward of the first station, and fifty marked males 
were liberated at 2.30 p.m., at station 3. This station was 
located 713 yards to leeward of the first station. At 3.30 
p.m. one male from station 2 reached the trap, and at 4.15 
p.m. one from station 3. 

Experiment JSfo. 7. 
Fair. Wind, north-west; average movement, 12 miles. 
Two traps, containing twelve female moths each, were set up 



350 THE GYPSY MOTH. 

at 8 a.m. At station 2, one-fourth of a mile to leeward of 
station 1, six marked males were liberated at 8.30 a.m., and 
at 2 p.m. seven more males were liberated at this station. 
At station 3, one-half mile to leeward of station 1, six 
marked males were liberated at 8.45 a.m., and at 2.15 p.m. 
eight others similarly marked were also allowed to escape 
at this station. There were no results from this experiment. 

Experiment JVo. 8. 

Fair. Wind, from nearly all directions ; average move- 
ment, 5 miles. Two traps, containing six female moths 
each, were set up at 8.30 a.m. At station No. 2, one-fourth 
of a mile to leeward of station 1, eight marked males were 
liberated at 9.50 a.m. At station 3, one-half mile to lee- 
ward of station 1, six marked males were liberated at 9.08 
a.m., and six other males similarly marked were liberated at 
a distance of sixteen yards to the right of station 1. One 
male moth from station 2 returned at 10.30 a.m. The wind 
shifted to east and south-west, and at 1.30 a heavy rain pre- 
vented all further work. 

The data concerning the direction and wind movement, 
given in these experiments, were kindly furnished by Mr. J. 
W. Smith, the Boston local forecast official, and, as the place 
where the experiments were performed was within four miles 
of the Boston observatory, the figures in all probability are 
approximately accurate for the locality. 

Remarks on the Above Experiments. 
These experiments show that, under favorable conditions, 
female gypsy moths will assemble males from various dis- 
tances up to half a mile, and it is possible that they might 
have been attracted from somewhat greater distances had 
males been liberated in larger numbers from stations more 
remote from the female. It must be borne in mind that 
these experiments were conducted under what would seem 
to be the most favorable conditions, namely, upon a level 
area, where a sweep of the wind could be obtained ; yet it 
may be possible that what was gained by the favorable con- 
ditions was in a measure offset by a slight weakening of the 
males caused by the handling necessary while marking them. 



ASSEMBLING. 351 

As shown by these records, males were assembled 427 yards 
(see experiment No. 6), 440 yards (see experiment No. 8), 
713 yards (see experiment No. (5) and 880 yards (see experi- 
ment No. 2). 

A series of experiments, to determine the manner in which 
the male gypsy moth recognizes the presence of the female, 
was made at the insectary and in the field, with the follow- 
ing results : — 

Experiment JVb. 9. 
July 25. To determine the effect of alcohol upon the 
antennae, as the shellac to be used later was dissolved in 
alcohol, the antennae of a male moth were thoroughly bathed 
in ninety-three per cent, alcohol at 10.50 a.m. The first 
effect of this application might well be called a complete 
intoxication. The moth lay for two or three minutes flat 
on the table without stirring. At 10.53 he began to move, 
but had only partial control of his limbs, and travelled with 
unsteady gait a short distance on the bench. By degrees he 
completely recovered his normal condition, and at 1.15 p.m. 
he mated with a female in a normal manner. 

Experiment JVb. 10. 
July 30. At 9.30 a.m., the wings of four unfertilized 
females were completely covered with shellac, after which 
the moths were placed in the experimental room, and two 
males in normal condition were liberated. At 10 a.m., 
a female attracted and mated with one of the males. At 
10.50 a.m., the other male was attracted to a second female, 
but did not mate. At 11.30 a.m., the same male was 
attracted to a third female, with the same results as in the 
preceding case. At 3 p.m., one of these females attracted a 
male, which mated with her at once. 

Experiment No. 11. 
July 30. At 9.30 a m., the dorsal surface of four females 
(with the exception of the wings) was coated with shellac 
varnish, the moths then being introduced into the experi- 
mental room with a number of normal males. At 10.30 
a.m., one female mated with a male. At 11.40 a female 



352 THE GYPSY MOTH. 

attracted a male, but did not succeed in mating. At 12 m., 
a female attracted a male, with the same result as in the pre- 
ceding case. 

Experiment JVo. 12. 
July 30. At 9.30 a.m., the head and thorax of four 
females were completely coated with shellac varnish, after 
which operation the moths became quite stupid and one of 
them seemed apparently dead. At 4.30 p.m., one of the 
females mated with a male, but none of the others mated. 

Experiment JVo. 13. 

July 30. At 10.15 a.m., four unfertilized females were 
coated with varnish along the sides of the thorax and abdo- 
men. They were then placed in a wire-gauze can, which 
was attached to a tree, in the YVoburn colony, at a height of 
about six feet from the ground. This trap was visited by 
thirty-eight males from 10.15 a.m. to 3 p.m. 

Experiment JVo. 14. 
July 30. Another can, containing four unfertilized females 
in normal condition, and used as a check, was visited by 
thirty-eight males from 10.15 a.m. to 3 p.m. 

Experiment JVo. 15. 
July 30. Another can, containing four unfertilized females, 
whose wings were covered on both surfaces with shellac, was 
exposed under similar conditions. This trap was visited by 
seventy-six males from 10.15 a.m. to 3 p.m. 

Experiment JVo. 16. 
July 30. A can containing four unfertilized females, with 
the whole of the body, except the wings, covered with shel- 
lac, was exposed under the same conditions. This trap was 
visited by only one male. A check can containing four un- 
fertilized females, in normal condition, exposed in the same 
manner and at the same place as those in the preceding 
experiments, to determine what would be the normal rate of 
assembling, was visited by seventy-seven males from 10.15 
a.m. to 4 P.M. 



ASSEMBLING. 353 



Experiment JVo. 17. 
August 1. A can containing four unfertilized females, 
with the last three segments of the abdomen coated entirely 
with shellac, was exposed as in the previous experiments, 
and was visited by twelve males from 10.15 a.m. to 4 p.m. 

Experiment JVo. 18. 
August 1. Another can, containing four unfertilized 
females, which were coated with shellac over the whole 
body, with the exception of the three posterior segments, 
was exposed under the same conditions as in the preced- 
ing experiments, and was visited by twenty-six males from 
10.15 a.m. to 4 P.M. 

Experiment JVo. 19. 
August 1. A can containing four unfertilized females, 
with the tips of their abdomens covered with shellac, so as 
to close the external openings of the body, was exposed 
under the same conditions as in the preceding experiments, 
and was visited by eleven males from 10.15 a.m. to 4 p.m. 

Experiment JVo. 20. 
August 2. A single unfertilized female, in normal con- 
dition, w T as placed in a small cardboard box, having a cheese- 
cloth top, and exposed on the branch of a tree, at a distance 
of five feet from the ground. This box was visited by 
twenty-eight males from 10.30 a.m. to 3 p.m. 

Experiment JVo. 21. 
August 2. A wire-gauze can, containing an unfertilized 
female that had been denuded of hair, but whose wings were 
in a normal condition, was exposed under the same con- 
ditions as in the preceding experiments, and was visited by 
thirteen males from 10.30 a.m. to 1 p.m. 

Experiment JVo. 22. 
August 2. This experiment was conducted under the same 
conditions and at the same time as preceding experiments, 



354 THE GYPSY MOTH. 

except that the can contained a female whose wings were 
removed close to the body. This trap was visited by four- 
teen males from 10.30 a.m. to 3 p.m. 

Experiment JVb. 23. 
August 6. A female, with all appendages and down re- 
moved, was suspended in a mosquito-net bag in the centre of 
a colony in Hawke's woods, Saugus. She received no visits 
from males up to 5 p.m. 

Experiment JVo. 24. 
August 6. Same place as above. At 10.45 a.m., a de- 
nuded female was suspended in a mosquito-bar box from a 
tree, at a height of five feet from the ground. At 5 p.m. she 
had received no visits from males. 

-Experiment JVo. 25. 
July 25. At 1.45 p.m., the antennae of two male moths 
were covered with shellac varnish. This produced no ap- 
parent effect upon the moths. The males were kept in close 
proximity to females during the remainder of the afternoon, 
but none of them attempted to mate. July 25. At 1.45 
p.m., the antennae of two males were covered with a coating 
of shellac, and the moths were then placed in a small card- 
board box with four unfertilized females. July 26, at 7 
a.m., the moths had not mated. 

Experiment JVb. 26. 
July 25. At 1.45 p.m., the antennae of a male moth, 
which had just begun to mate with a female, were covered 
with shellac varnish. This apparently produced no effect, 
as the male did not leave the female until 2.20 p.m. 

Experiment JVo. 27. 
July 25. At 3.48 p.m., a fresh, vigorous male was 
deprived of both fore legs and then placed on the experi- 
mental bench near a female. The odor of the female was 
driven towards him by the use of a fan, and he at once recog- 
nized her presence, and at 3.51 p.m. the moths mated. 



ASSEMBLING. 355 



Experiment JVo. 28. 
July 26. At 8.50 a.m., one male moth, with three legs 
removed, was placed on the experimental bench three feet 
from four unfertilized females. At 9 a.m., he flew to the 
partially drawn curtain and remained there until 10.45, when 
he flew down from the window and mated with a female. 
At 11 a.m. his antennae were cut off, but this did not pro- 
duce any appreciable effect. They remained together until 
11.30. After leaving the female, he remained inactive dur- 
ing the rest of the day. 

Experiment JVo. 29. 
July 26. At 8.50 a.m., a male moth, with its wings 
removed, was placed on the experimental bench at a distance 
of three feet from four unfertilized females. At 10.20 a.m., 
he approached rapidly within two inches of the females, but 
eventually crawled away to a distance of three feet from 
them. At 1.40 p.m., he was placed near a female on the 
bench, but after a few minutes went away from her. At 
2.05, he was placed within one foot of a female, and after 
crawling slowly toward her, mated with her. 

Experiment JVo. 30. 
July 26. At 8.50 a.m., a male moth with both antennae 
removed was placed three feet from four unfertilized females. 
At 9, he had crawled a distance of one foot toward the 
females. He remained quiet until 11 a.m., when he was 
placed close to a female moth. He, however, paid no atten- 
tion to her, and, up to 5 p.m., made no attempt to mate. 

Experiment JVo. 31. 
July 26. At 9.28 a.m., the antennas of a small male were 
coated with shellac and he was placed on the experimental 
bench, at a distance of two feet from a number of females. 
At 11.30, he had made no effort to mate with any of them. 
He was then placed on a box containing a large number 
of unfertilized females, but showed no animation. Other 
males, with their antennae not coated, were continually hov- 



356 THE GYPSY MOTH. 

ering about the box. The male in question remained quiet 
until 5 p.m. 

Experiment JSTo. 32. 
July 26. At 3 p.m., the eyes of three male moths were 
covered with shellac, and they were then placed within two 
feet of two mature, unfertilized females. At 3.05, one male 
flew to the females and attempted to mate, but was unsuc- 
cessful. At 3.25, another male approached the females, in 
the same manner, but with no better success, but at 3.35 
two of the males were successful in mating with two 
females. 

Experiment JYo. 33. 

July 27. At 9.30 a.m., two males with eyes and a part 
of the head covered entirely with shellac were placed on the 
experimental bench, three feet from four unfertilized females. 
At 12 m., one of these males began to fly about, and at 1 
p.m. he was found mating with a female five feet from the 
place where he was at noon. At 1.45 he left the female, and 
at this same time the other male, whose eyes had been cov- 
ered with shellac, mated with a female and remained with 
her up to the time the experiment closed, at 5 p.m. 

From the preceding experiments the following conclusions 
may be drawn : — 

1. Coating the abdomen of the female with varnish or 
denuding it of hair deprives her, in a great measure, of the 
power to assemble males. The amount of assembling which 
takes place under these conditions varies inversely with the 
amount of body surface coated or denuded. 

2. The presence or absence of wings in either sex does 
not greatly influence the assembling process. 

3. The sense of sight is not necessary to the operations 
of assembling. 

4. The antennas are absolutely necessary to the male in 
locating the female, and without them assembling is impos- 
sible. It is a well-known fact that the males of this species 
coming from any distance always approach from the lee- 
ward side of the female, thus apparently indicating that the 
assembling is the result of an odor given off by the female, 
and carried by the wind. 




' 



EXPLANATION OF PLATE 53. 





Drawn by J. H. 


Emerton. 


I. 


Calosoma frigidum Kirby, 


natural size. 


2. 


Menecles insertus (Say), 


a a 


3- 


Podisus cynicus (Say), 


(( (C 


4- 


Podisus serieventris Uhl., 


(C u 


5- 


Polistes pallipes St. Farg., 


(( a 


6. 


Theronia melanocephala (Brulle), " 


7- 


Pimp/a pedalis Cress., female 


a a 


7 a. 


" " " male, 


a a 


8. 


Pimpla tenuicornis Cress. X 


4- 


8 a. 


(C (t " 


natural size. 


9- 


Formica subsericea Say, worker X 4. 


9 a. 


(( u a C( 


natural size. 


10. 


Diglochis omnivorus (Walk.) 


female X 8. 


io a. 


a (( . " 


" natural size. 


io b. 


cc ii " 


male X 8. 


IO c. 


(C U ii 


" natural size. 


ii. 


Achcetoneura fernaldi Williston, female X 4. 


ii a. 


a a a 


" natural size 


nb. 


a u a 


foot of female. 


II c. 


a a a 


" male. 


ii d. 


a a a 


face of female. 


ne. 


a a a 


" maie. 


12. 


Elachiptera dispar Williston 


X 8. 


12 a. 


a a a 


natural size. 


13- 


Phlczothrips sp. ? X 32. 




14. 


Nothrus sp. ? X 32. 




i5- 


Trombidiutn bulbipes Pack. 


X 32. 



ASSEMBLING. 357 

Concerning the assembling process in the BombycicUe, the 
late Prof. C. V. Riley wrote as follows: "The power of 
assembling among certain moths, for instance, especially 
those of the family Bombycidee, is well known to entomolo- 
gists, and many remarkable instances are recorded. . . . 
Now, in the moths of this family the male antennae are elab- 
orately pectinate, the pectinations broad and each branch 
minutely hairy. These feelers vibrate incessantly, while in 
the female, in which the feelers are less complex, there is a 
similar movement connected with an intense vibration of the 
whole body and of the wings. There is, therefore, every 
reason to believe that the sense is in some way a vibratory 
sense, as, indeed, at base is true of all senses ; and no one 
can study the wonderfully diversified structure of the an- 
tennae in insects, especially in males, as very well exemplified 
in some of the commoner gnats, without feeling that they 
have been developed in obedience to, and as a result of, 
some such subtle and intuitive power, as this of telepathy. 
Every minute ramification of the wonderfully delicate feelers 
of the male mosquito, in all probability, pulsates in response 
to the piping sounds which the female is known to produce, 
and doubtless through considerable distance " ( " Insect Life," 
Vol. VII, page 39). 

In view of the fact that the males of the gypsy moth will 
assemble nearly as readily to empty boxes, bags, etc., in 
which females of the species have been previously confined, 
as to the females themselves, we are led to believe that with 
this insect, at least, the process is one depending upon the 
sense of smell alone.* 

On Tkapping Males. 

The following experiments were made under my direction 
by Mr. H. N. Reid in 1893, for the purpose of determining 
whether it is possible to trap the males of the gypsy moth, 
in any infested region, to such an extent that there would not 
be enough left to mate with any considerable number of 
females, so that a large proportion of the females would be 
compelled to lay infertile eggs, and therefore greatly reduce 

* In one case males were found to visit an empty pasteboard box which had con- 
tained female moths three days before. 



358 THE GYPSY MOTH. 

the number of gypsy moths in that locality the following 
season. 

For this purpose wooden boxes, 12 by 8 by 3 inches, 
were made, without top or bottom, these being covered with 
brass wire gauze. A hole was bored in one end for the in- 
troduction of the female moths, and this was closed by a 
cork. Several different substances were used, on these traps, 
to capture the males when they flew against them, as mo- 
lasses, raupenleim, sticky fly-paper, etc. Molasses proved 
of no value, as it ran too easily, and was not sticky enough. 
The raupenleim was not sticky enough, and soon dried on 
the outside, so that it would not hold the males when they 
flew against it. Sheets of sticky fly-paper, with holes 9 by 
4 inches cut from the centre, were tacked over the gauze ; 
these proved very efficient in securing and holding the 
males, but it was necessary to replace them with fresh ones 
frequently, and, to avoid this, they were painted over with a 
preparation of castor oil and resin, which proved to be bet- 
ter for the purpose required than the original fly-paper. 
When a trap was first put up a sheet of fly-paper was 
tacked on it, and each time the trap was visited the cap- 
tured males were removed and the paper recoated so far as 
necessary. This gum was found to keep in good condition 
for several days, unless a large number of males were caught 
in it, or the trap was in a very dusty pjace. Even when the 
males were not caught the first time they touched the paper, 
they were so persistent that they would immediately fly 
against it again, and be caught in a few minutes. 

The fly-paper was removed from one trap (No. 14) after a 
few days, and a pan of water with a little kerosene on the 
top of it was suspended directly beneath the trap. On ac- 
count of the rapidity with which the males fly, and the light- 
ness with which they struck the trap, it was not expected 
that they would be caught in the kerosene ; but, being very 
persistent, in trying to go under the trap from one side to 
the other they came in contact with the kerosene and were 
destroyed. This plan was not very satisfactory, not only 
on account of the expense, but also because the kerosene and 
water were so frequently spilled by the wind. 

To obtain " bait" for these traps, it was found better to 



TRAPPING MALES. 359 

collect the female pupae and allow them to emerge in con- 
finement, because in this way the matter could be controlled 
more successfully than in any other. It was also found that 
the traps attracted best when placed but a few feet above the 
ground. 

Fifteen traps were used during these experiments. No. 7 
was removed after six days, to be placed elsewhere, as noth- 
ing was captured on it up to that time. No. 14 had sticky 
fly-paper on it the first five days, during which time it 
caught two hundred males. The fly-paper was then removed, 
and a pan containing the water and kerosene was suspended 
an inch or two below the trap. During the next twelve days 
sixty-five males were captured in the pan. The traps were 
put out from July 31 to August 10, and were taken in from 
August 19 to August 30. The records of the traps are 
given below : — 

No. 1 was put out July 31, and taken in August 19, having 
captured 82 males. 

No. 2 was put out July 31, and taken in August 19, having 
captured 34 males. 

No. 3 was put out August 1, and taken in August 28, having 
captured 175 males. 

No. 4 was put out August 1, aud taken in August 28, having 
captured 87 males. 

No. 5 was put out August 2, and taken in August 30, having 
captured 36 males. 

No. 6 was put out August 2, and taken in August 25, having 
captured 88 males. 

No. 7 was put out August 2, and taken in August 8, having 
captured nothing. 

No. 8 was put out August 8, and taken in August 30, having 
captured 167 males. 

No. 9 was put out August 8, and taken in August 26, having 
captured 37 males. 

No. 10 was put out August 8, and taken in August 30, having 
captured 85 males. 

No. 11 was put out August 8, and taken in August 26, having 
captured 213 males. 

No. 12 was put out August 8, and taken in August 28, having 
captured 131 males. 



360 THE GYPSY MOTH. 

No. 13 was put out August 9, and taken in August 30, having 
captured 163 males. 

No. 14 was put out August 10, and taken in August 30, having 
captured 265 males. 

No. 15 was put out August 10, and taken in August 28, having 
captured 208 males. 

Summary. 

Omitting No. 7, which remained out but a few days, the 
whole number of males taken by all the traps was 1,771. 
The smallest number taken by any one of them was 34, the 
largest number was 265 and the average 126.5. 

During the months of July and August, 1894, these ex- 
periments were repeated by Mr. F. C. Schrader and four 
other assistants. One hundred and ninety-one traps were 
put up in the worst infested districts of Maiden, Medford 
and Everett, and kept in working order during the time 
that the males were flying. The traps were visited every 
day, fresh gum applied when necessary, new females put 
into the traps as often as needed, and careful records were 
kept of the results. The trapping season began July 19, 
and closed August 13. Two different styles of traps were 
used. The first kind was made of two-quart tin varnish 
cans, from each of which was suspended, about two inches 
below it, a tin base 9 by 12 inches, dished, so as to slope 
from the edges toward the centre, and attached by two strips 
of tin to a loop on each of the narrow sides of the can. A 
strip of tin was removed from each side of the can, and this 
was replaced by brass wire gauze. The unfertilized females 
were placed in the can, through the hole at the top, which 
was kept closed by a cork stopper. The traps were sus- 
pended from branches of trees by hooks eight inches long, 
attached to the handle of the cans. 

The other kind was a four-leaved wooden trap, commonly 
called the "Shaw" trap (Plate 54), devised by Mr. H. J. 
Shaw. It consisted of a horizontal base board of half-inch 
lumber, one foot square, with narrow grooves at right angles 
across the middle of the upper side. Two thin boards, twelve 
inches wide and seven inches high, notched together in the 
middle at right angles, were secured in the grooves in the 
base board, thus forming four vertical wings. An opening 



<D P. 

as 



2 *? 







TRAPPING MALES. 361 

was cut in the lower edge of the vertical boards at the 
centre, and in this opening was secured a cylindrical wire- 
gauze cage, three inches in diameter and height, and with a 
convex tin top and bottom. The unfertilized females were 
placed in this cage through a round hole in the top, which 
was kept closed by a cork. The trap was suspended by 
means of a hook fitting into a wire loop at the centre of the 
top of the vertical wings. Several other kinds of traps of 
various patterns were tried, but none proved so satisfactory 
as the two described above ; and of these the four-leaved 
wooden trap proved to be the best, as it allowed the females 
to be exposed to the air on all sides, and also because it pre- 
sented a greater area of the sticky surface. The majority of 
the males were caught on the base boards of the traps, the 
greater number invariably being taken on the leeward side. 
The ' ' bait " used in all of these traps was unfertilized 
female moths bred from pupae in confinement, though the 
pupae themselves, and dead and fertilized females, were also 
tried for the purpose of ascertaining whether they would 
attract the males. It was found advantageous, when keep- 
ing pup33 in confinement, to moisten them with a fine spray 
of water from time to time, to keep them from drying up so 
much as to prevent them from emerging. The " bait" in 
the traps was renewed as often as necessary. The best 
means of carrying the newly emerged females was found to 
be a cloth-lined box, as they would cling to the lining, and 
could be transported in this way with little or no injury. 
The traps were painted over with a sticky gum composed of 
sixty per cent, of crude resin and forty per cent, of crude 
castor oil. The resin and oil were melted together, and 
applied, while warm, to the traps by means of a flat varnish 
brush, care being taken not to put the gum on the gauze. 
Most of the traps required repainting about every second 
day, though some required it oftener. A small pointed 
trowel was used in removing the captured males from the 
glue, and a pole with a small hook at the end was used in 
removing and replacing the traps in the trees. The trapping 
operations were closed August 13, for lack of " bait," and 
also because so few males were then captured that it did not 
seem wise to continue the work. 



362 THE GYPSY MOTH. 

It was repeatedly demonstrated, in different towns and 
with different traps, that they can be handled much more 
easily and will capture more males when hung low, or placed 
near the ground, than when they are placed high in the trees. 
The gum, when made in the proportion given above, runs and 
drips in hot weather and in the warm sunshine, more on the 
tin than on the wooden traps, so that great care was required 
in placing them in certain localities near residences, lest the 
dropping gum should do harm. The adhesive power of this 
gum is remarkable. Two young birds were caught on the 
foot board of the tin traps in Maiden. They were both dead 
when found, and showed evidence of desperate efforts to 
extricate themselves. In the struggle they had pulled out a 
large quantity of feathers, and, in the case of a half-grown 
English sparrow, which lay upon its side with the head 
directed from the trap, the feathers adhered so firmly that 
the bird could not be pulled off without tearing the body 
apart. Careful observations showed that at least ninety per 
cent, of the male moths were captured on the foot board. It 
was also found that where the moths are abundant the traps 
can be used advantageously within ten rods of each other, or 
in adjacent lots. 

The essential point for the successful working of a moth 

trap is to have the female well exposed on all sides, so that 

the wind may pass freely over her body, and carry the odors 

away without obstruction in any direction that the air may 

be moving ; and, at the same time, she should be sufficiently 

protected to insure her existence as long as possible. The 

average length of life of unfertilized female moths, in the 

wooden, four-leaved traps, was seven days. One female 

moth, put into the trap July 31, was alive August 9, but 

was dead at the time of the next visit, August 11. Another 

female was put into a trap August 1, and died August 11. 

In some cases the moths put into the traps were caught in 

the gum, which worked in at the bottom of the cans, and 

died in a day or two. In the tin traps the female moths did 

not live more than two or three days, and those in the old 

wooden box traps used the year previous did not live any 

longer, seldom exceeding two days. 

In some instances, when there were no unfertilized females 




PLATE 55. Female moths depositing 1 their egg-clusters on the trunk 
of an oak tree, Saugus, 1895. 



OVIPOSITION. 363 

for " bait," fertilized moths, dead moths or female pupae 
were used. The fertilized females attracted the males in 
about half the cases where they were used. Of eight traps 
" baited " with fertilized females, three caught nothing, two 
caught one each, two caught two each and one caught four- 
teen, being an average of two and one-half each. The aver- 
age catch of the same traps, "baited" with unfertilized 
females, was twenty and eight-tenths each. In nineteen of 
the traps dead females were used at times, but they proved to 
be of little value, for only five out of the nineteen attracted 
any males. The total number of females used was twenty- 
three, and only twenty-four males were captured by such 
" bait." In some cases, female pupae were used in the traps, 
and gave rather surprising results, which seem to indicate 
that the pupae possess in some degree the power to assemble 
male moths, as twenty-one female pupae attracted seventy- 
two males. 

The following is a summary of the results obtained : 
191 traps; total catch, 9,767 males; average, 51.2 each; 
maximum catch, 431 males ; minimum catch, ; maximum 
catch by a single female, 420 ; minimum catch by a single 
female, 0. 

After the trapping season was over, the localities in Med- 
ford, where the greatest number of males was captured, 
were carefully explored and the egg-clusters collected. In 
the latter part of December these eggs were carefully ex- 
amined and their fertility determined, with the following 
results : of 659 egg-clusters examined, 16, or 2.4 per cent., 
proved to be infertile. As a check on the work, an equal 
number of egg-clusters taken from places not trapped for 
males were collected and examined, and all proved fertile. 

Oviposition. 

The abdomen of the female is so heavy before depositing 
her eggs that she simply clings head upward to the trunk 
of a tree or other object on which she happens to be rest- 
ing (Plate 55) ; and when preparing to lay, and even during 
the process of depositing the egg-cluster, she drops or scat- 
ters more or less eggs accidentally. A small hairy area is 
first formed by rubbing the abdomen over the surface, thus 



364 THE GYPSY MOTH. 

depositing a small quantity of hair, which is caused to ad- 
here, probably by a slight discharge of fluids. One egg 
is fastened to the surface, another is placed beside it and 
others on each side of these. As soon as the foundation is 
started, other eggs are laid upon it and the mass is built 
along ; that part of the cluster next to the surface on which 
the moth rests is always kept a little in advance of the 
eggs laid on top of it, and is the widest part of the 
structure. The eggs when laid are covered with an ad- 

Do 

hesive fluid, which not only causes them to adhere where 
they have been placed by the ovipositor, but also causes 
the abdominal hair of the female, which she rubs off by the 
continual movement of the abdominal segments, to adhere 
to them. As laying progresses, the abdomen shortens, 
and the hair from the under side of the anterior segments 
furnishes the covering for the last-laid eggs. 

The term layer may properly be applied to the eggs that 
are deposited on the surface upon which the moth is rest- 
ing, for they conform to that surface, however smooth or 
uneven it may be, but those outside of this layer are packed 
in very irregularly. In nearly every case where the eggs 
are laid upon a vertical or nearly vertical surface, the lay- 
ing is done from below upwards, the lower eggs being the 
first deposited, while the upper ones are the last. In gen- 
eral, from two to three days are required for oviposition, 
but the time is subject to considerable variation. The 
greater part of the egg-cluster is usually deposited during 
the first twenty-four hours. In one case a large female 
moth which began laying at 6 p.m., Aug. 6, 1895, did not 
complete her egg-cluster until 11.30 a.m., August 16. The 
female does not usually deposit all the eggs contained in the 
body. In the case of the female mentioned above, there 
were 201 eggs remaining in the abdomen of the moth, while 
the egg-mass which she had deposited contained 794 eggs. 

Eggs removed by Dissection of Female Moths. 

The female moths are often attacked while laying, and 
mutilated or entirely consumed by a few insectivorous birds 
and predaceous insects. Of the latter, the large wood ants, 
Caiivponotus jpennsylvanicus (De Gr.), sometimes kill the fe- 



PARTHENOGENESIS. 365 

male moths, gnaw open the abdomen, and, after removing 
the egg-mass, drag it to their nests. With the discovery 
of these facts the question naturally arose, whether the 
ecrorg thus removed from fertilized females would hatch and 

Do 

thus start new colonies in the places to which they had been 
carried. To settle this point, during the summer of 1895, 
studies were made on fifty female moths. Some of these 
moths were taken when the egg-cluster was about one-third 
completed, some when the egg-cluster was one-half com- 
pleted, some when two-thirds, and others which had very 
nearly completed laying. These moths were dissected, and 
all of the eggs still remaining in the abdomen removed and 
preserved in boxes. Examinations of these eggs, made 
subsequently, showed that none of them were fertile. 

A part of the egg-cluster deposited by twenty-five of 
these moths was preserved, all of which proved more or 
less fertile. This seems to demonstrate that, notwithstand- 
ing the mating of the moth, the eggs are not fertilized till 
during the process of laying. 

Parthenogenesis . 

Parthenogenesis, or reproduction by means of the eggs of 
unfertilized females, was thought to offer an explanation for 
the existence of certain peculiarly situated colonies in the 
infested territory. As has been previously stated, cater- 
pillars are sometimes dropped uninjured by the birds when 
they are carrying them away to feed their young ; or they 
may spin down from the trees upon passing teams or ani- 
mals, and be carried to greater or less distances and then 
escape to suitable food plants, where they can feed and 
pass their transformations. If a single caterpillar should be 
carried, in any such way, to a distance from any colony 
greater than males could be attracted, and from it should 
emerge a female moth, she would doubtless lay her eggs, 
and, if parthenogenesis occurs in this moth, these eggs 
might hatch, even though no male had been present to mate 
with her. 

To ascertain whether eggs laid by unfertilized females 
will hatch, in July and August, 1893, 990 female pupae were 
put in small pasteboard boxes and kept under a variety of 



366 THE GYPSY MOTH. 

circumstances, but all at the normal out-door temperature. 
Some were kept covered with cheese cloth, others with the 
regular box covers, and still others were kept covered a 
part of the time with the covers and the rest of the time 
with cheese cloth. One hundred and sixty of these pupre 
were from larvae raised in confinement, while the rest were 
collected in the field. Two hundred and thirty-three moths 
emerged and laid their eggs, but without that regularity 
that characterizes the egg-clusters of fertilized females. 
Most of the females laid a considerable number of esrors. 

Do 7 

though four laid no eggs but deposited some of their hair ; 
one laid only a single egg, while two other females laid four 
and five eggs respectively. The boxes containing these eggs 
were kept under the same conditions as other boxes which 
contained fertile eggs, which hatched at the usual time in 
the spring ; but no trace of embryonic development could 
be discovered within them during the fall, and they were 
again critically examined the last of January, 1894, when 
they were found to be more or less shrunken, and showed 
no sign of an embryo within, as is the case with fertile eggs. 
Early in the spring a piece of glass was glued over the top 
of each box, so that the young caterpillars could not escape, 
should any of the eggs hatch. They were daily inspected 
till after the time when they should have hatched, and then 
once a week till July, and less frequently till October, 1894, 
but not an egg hatched. While this experiment does not 
prove that parthenogenesis does not sometimes occur in the 
gypsy moth, it would seem to indicate that it is probably 
of rare occurrence. A few cases have been reported in 
Europe. Carlier states that he has seen three generations 
without mating having taken place, but the last genera- 
tion gave only males. Siebold, who refers to this case 
in " Entomologische Zeitung, Stettin," Vol. XXII, page 
443, expresses some doubt, since no exact account of events 
was given. Weijnbergh, however, has given a very com- 
plete account of breeding this species from unfertilized 
eggs for three generations, until, at last, the eggs dried 
and brought his observations to a close. Dohrn, who 
reports this case in "Entomologische Zeitung, Stettin," 
Vol. XXXII, page 30, expresses the opinion that the dry- 



EGG-CLUSTERS OF UNFERTILIZED FEMALES. 367 

ing up of the eggs of the last brood was not due to their 
parthenogenetic characteristics, but to outside influences, 
and further states that it would be premature to limit the 
vitality of the products of parthenogenesis to two genera- 
tions. It is a matter of regret that Weijnbergh did not 
examine the eggs each fall, and see whether the embryo 
had formed; for, had this been found, there would have 
been greater reason to have supposed that the eggs had 
dried up because of outside influences, as Dohrn conjectured. 
Mr. W. J. Pearce of Bath, England, reports in " The Ento- 
mologist," Vol. XII, page 229, that he had a female of this 
moth, which had not mated, lay eggs which hatched the 
following year. 

Egg-clusters or Unfertilized Females. 
The egg-clusters deposited by unfertilized females, in the 
experiments on parthenogenesis, in 1893, were, as a rule, 
irregular, scattering and poorly covered with hair. As 
these were all laid in boxes, it was thought that it might be 
due, in part at least, to the smoothness of the box, which 
did not allow the moth as good a foothold for oviposition 
as is afforded by the surfaces usually selected for the pur- 
pose, such as the rough bark of trees, etc. The observa- 
tions of the field inspectors led them to various conclusions, 
some contending that unfertilized females never lay the 
regular egg-clusters characteristic of the fertilized female, 
while others were of the opposite opinion. Investigations 
were made during the summer of 1895, to learn whether it 
is possible to determine, from the form and completeness of 
an egg-cluster, whether the eggs contained in it are fertile. 
August 2, twenty-five recently emerged, unfertilized female 
moths were placed in a cage, made by tacking cheese cloth 
over a hoop, which projected from the trunk of a white oak 
( Quercus alba) . This species of tree was selected because 
the bark is of such a nature as to give the moths the most 
favorable opportunity for egg-laying. At the end of two 
weeks, all the moths being dead, the cage was opened and 
six very imperfectly formed egg-clusters were found. They 
were, in fact, simply small patches of eggs, with but little 
of the usual covering of hair. October 10, the eggs were 



368 



THE GYPSY MOTH. 



shrivelled, and the clusters partly washed away by the rains. 
From these as well as other observations made this season 
it seems more than probable that a female gypsy moth that 
has not mated does not make a perfect egg-mass, and that 
an experienced observer may distinguish in most cases an 
egg-cluster that is infertile from one that is fertile. 

In-and-in Beeeding. 

A cluster of eggs laid by one female gypsy moth was 
placed in a breeding cage in the spring of 1893, to deter- 
mine whether the two sexes would emerge at the same time, 
mate and lay fertile eggs. This was for the purpose of 
ascertaining whether it would be possible for a fertile 
female, if transported to a new region, to lay eggs capable 
of establishing a new colony ; or, if a single cluster of eggs 
should be carried outside of the infested region, whether a 
new colony would result. The eggs used in this experi- 
ment commenced hatching May 5, 1893, and the caterpillars 
were fed on apple leaves till they reached maturity, when 
they pupated. The moths emerged as indicated in the fol- 
lowing table : — 



Date. 


June 
20. 


July 
1. 


July 
2. 


July 
3. 


July 
4. 


July 
5. 


July 
6. 


July 

7. 


July 
8. 


July 
9. 


July 
10. 


July 

12. 


Total. 


Male, . 
Female, 


3 


5 


8 

2 


32 

16 


13 

15 


60 

62 


76 
69 


26 
20 


2 20 
4 16 


19 


3 

7 


267 

211 





In all there were 478 moths, 267 males and 211 females, 
which mated as readily as those from different egg-clusters ; 
and, as their eggs proved fertile, there is every reason to 
believe that, under favorable circumstances, this cluster of 
eggs could have established a colony of moths. See " The 
Entomologist," Vol. XIX, page 281 (1886). 

Inteenal Anatomy. 

The following description of the internal anatomy of the 
different stages of the gypsy moth was prepared by Mr. A. 
H. Kirkland. 



PLATE 58. 




EXPLANATION OF PLATE 58. 



Drawn by A. H. Kirkland. 



i. Internal anatomy of larva of gypsy moth X 2 : nc, nerve 
cord; sg., silk gland; ce., oesophagus; b., brain; as., 
anterior stomach; dv., dorsal vessel; ps., posterior 
stomach; ro., reproductive organ; mv., malpighian 
vessels; i., intestine; r., rectum. 

2. Internal anatomy of larva about to pupate X 2 : as., ante- 

rior stomach; ps., posterior stomach; dv., dorsal ves- 
sel ; ro., reproductive organ. 

3. Section through anal segment of larva about to pupate, 

showing development of cremaster in anal shield X 4 : 
as., anal shield; c, cremaster; r., rectum. 

4. Section through head of larva about to pupate, showing the 

development of the antenna cases beneath the larval 
head covering X 4: dv., dorsal vessel; ce., oesophagus; 
b., brain; a., antenna case. 

5. Internal anatomy of female pupa X 2: dv., dorsal vessel; 

ro., rudimentary accessory organs of reproductive sys- 
tem ; r., rectum. 

6. Internal anatomy of female moth X 2: od., oviduct; cp., 

copulatory pouch; nc, nerve cord and ganglia; s., 
atrophied stomach; b., brain; dv., dorsal vessel; r., 
rectum ; ag., accessory glands of reproductive system. 

7. Right silk gland of full-grown larva, enlarged. 

8. Posterior tip of silk gland, greatly enlarged. 

9. Part of malpighian vessel, greatly enlarged. 

10. Part of dorsal vessel of imago, showing aortic arch. 



Drawn by R. A. Coolev. 



Micropyle of egg with surrounding rosette, greatly enlarged. 
A part of the same, still more enlarged 



INTERNAL ANATOMY. 369 

The figures of the internal anatomy were made from dis- 
sections of alcoholic specimens of the different stages, the 
work being performed at the entomological laboratory of 
the Massachusetts Agricultural College. In preparing the 
material for dissection the insects were first placed for 
twenty-four hours in fifty per cent, alcohol, then, for the 
same period of time, in seventy-five per cent, alcohol, and 
then kept in commercial alcohol until needed for use. The 
dissections were made under water, by using a small wax- 
bottomed dissecting pan. The dissections of the pupae were 
not wholly satisfactory, since the rapid breaking down of 
the larval organs and the correspondingly rapid development 
of the organs of the imago obscured the relations of the 
different parts, and made the correct interpretation of them 
a difficult task. The longitudinal section of the pupa, as 
shown in Plate 58, Fig. 5, is a composite figure, made 
up from the dissections of several pupge from five to seven 
days old. 

The Alimentary Canal and its Appendages. 
From the medium large mouth cavity the oesophagus 
(Plate 58, Fig. 1, oe) leads back through the oesophageal 
collar formed by a division of the double commissure which 
connects the brain (1)) with the sub-cesophageal ganglion in 
the first thoracic segment. Here it expands into a peculiar 
thin- walled organ, which, from its position and size, may be 
called the anterior stomach (as). This anterior stomach, 
which is practically an enlarged continuation of the oesoph- 
agus, is distinctly separated from the posterior stomach, 
stomach proper, by a well-defined constriction formed by a 
strong sphincter muscle, possibly valvular in function. 
The anterior stomach fills the thoracic and a part of the first 
abdominal segments. A marked distinction from the pos- 
terior stomach is the fact that it is not supplied with the 
prominent annular muscle bands which are characteristic of 
the latter organ, although it possesses both annular and 
longitudinal muscle fibres. In the larger caterpillars it is 
usually distended by a dark, viscid, semi-fluid mass, con- 
taining the recently devoured food, and, as shown by micro- 
scopic examination, numberless bacteria. The posterior 



370 THE GYPSY MOTH. 

stomach (ps) extends backward from the anterior stomach 
to the eleventh segment and nearly fills the body cavity. 
The contents of this organ are of a more solid nature than 
those of the anterior stomach. In the eleventh segment 
this organ tapers abruptly to form the short intestine (i), 
which has two enlargements, separated from each other by 
a sharp constriction. Between the stomach and the intes- 
tine, and also where the intestine enters the rectum, there 
is a well-marked constriction. In the last body segment 
the intestine expands into the large distended rectum (r) , 
which completely fills the cavity and discharges at the anus 
beneath the anal shield. Six narrow longitudinal muscles 
extend the entire length of the alimentary canal. These 
muscles form six definite depressions on the intestine and 
rectum, and give to the excrement of the larva its peculiar 
incised appearance. 

The malpighian vessels (Fig. 1 , mv) consist of six double 
convoluted tubes which are attached to the walls of the pos- 
terior stomach .and discharge into the intestine. These ves- 
sels are simply convoluted tubes (Fig. 9), and do not pos- 
sess the bulbose lateral enlargements found in many other 
Lepidoptera. They are composed of a thin outer membrane 
and an inner layer of thick-walled nucleated cells, arranged 
around a central lumen, some parts of which, in the alco- 
holic specimens, are often filled with a yellow-brown crys- 
talline mass (urates) . Fresh malpighian vessels macerated 
in water give quantities of minute crystals. I have been 
able to demonstrate the presence of uric acid in these ves- 
sels by the use of the " murexid " test. 

Small white granules are occasionally found deposited 
throughout all the different tissues of the larva, but, owing 
to their extremely small size, I have been unable to collect 
a sufficient quantity for analysis. In similar granules re- 
moved from the tobacco worm (Proloparce celeus) I have 
found uric acid, as shown by the "murexid" test, and 
phosphoric acid, as demonstrated by the reaction with am- 
monium molybdate. 

The silk glands, two in number, lie along the lateral walls 
of the body cavity of the larva. Each gland consists of a 
small thread-like tube, which leads forward from the poste- 



INTERNAL ANATOMY. 371 

rior part of the body, gradually enlarging in the seventh 
segment, thence extending forward to the fourth segment, 
where it bends on itself and leads backward and upward to 
near the middle of the eighth segment. Here it reaches its 
maximum diameter. It bends downward and gradually 
tapers again to a thread-like duct, which extends forward, 
and, after a more or less irregular course, discharges at the 
spinneret on the under side of the labium. 

In the full-grown larva (Fig. 1, sg) these glands are dis- 
tended with the silk-forming fluid ; in those which have spun 
their cocoon (Fig. 2) they have contracted to less than 
one-half of their original size. One of these glands is 
shown in Fig. 7, and its extreme posterior tip in Fig. 8. 

When the caterpillar is ready to pupate (Fig. 2), the 
alimentary canal is emptied of its contents, the anterior 
stomach (as) shrinks to less than one=half of the diameter 
of the posterior stomach (ps), the latter having also 
shrunken to about one-half of its original diameter. The 
intestine and rectum undergo a corresponding diminution. 
In the pupal stage (Fig. 5) the anterior stomach grows still 
narrower, the posterior stomach and rectum shorten, while 
the intestine, although less than one-fourth of the diameter 
of the larva, elongates to nearly twice its original length. 
In the imago (Fig. 6) the digestive system is atrophied, the 
anterior part being represented by a slender thread-like 
remnant of the oesophagus and anterior stomach, while the 
posterior stomach has been transformed into the small 
shrunken stomach (Fig. 6), at the hinder end of which may 
be found the remains of the malpighian vessels. A slender 
intestinal tube connects the stomach with the rectum (r) , 
which lies in the upper posterior part of the abdominal 
cavity, and is usually filled with a thick cream or salmon 
colored fluid. 

It is interesting to note that the digestive system of the 
male imago does not appear to have undergone so marked 
a degeneration as that of the female. The stomach is much 
better developed, and the relation of the different parts can 
be more clearly demonstrated. 



372 THE GYPSY MOTH. 



Dorsal Vessel or Heart. 

This organ, in a caterpillar, is a simple longitudinal tube 
(Fig. 1, dv), lying immediately beneath the dorsal line and 
extending the whole length of the body. It is closed at the 
posterior end, while the anterior end opens at the base of the 
brain. Bands of muscle fibres, placed more or less oblique- 
ly, appear in the walls of the organ, while it is supported at 
the sides by fan-shaped muscles (alae) which are attached 
to the upper body walls. 

In the pupal stage (Fig. 5, dv) a marked bend is found 
near the anterior end of the dorsal vessel, while faint muscle 
fibres can be traced, extending from the bend to the dorsal 
wall of the thorax. 

In the imago (Fig. 6) the dorsal vessel (dv) follows 
the contour of the upper surface of the abdomen, bends 
abruptly downward at the junction of the abdomen and 
thorax, enters the thoracic cavity, bends obliquely upward 
to the dorsal wall, where it is firmly attached by muscle 
fibres, then extends downward and slightly backward, 
thence forward to the head, where it terminates at the base 
of the brain. I have been unable to discover any aortal 
chamber, such as was found by Burgess in Anosia plexrppus, 
although the aortal arch (Fig. 10) is well defined. 

Respiratory System. 

This system is not figured in the plates, but possesses the 
general features common to Lepidoptera. The spiracles 
open internally by short tubes which communicate with two 
long lateral tracheae. These extend the whole length of the 
body, and give off ramifications to all the organs. Opposite 
the spiracles are clusters of tracheae of medium size, which 
are distributed over the surface of the alimentary canal. 
The tracheae are composed of an outer semi-transparent 
sheath, made up of large, thin cells, the nuclei of which are 
readily revealed by staining with haematoxylin. Within 
this sheath is a chitinous tube, bearing on its inner surface 
a fine spiral ridge, which gives the tracheae their distinguish- 
ing characteristic. 



INTERNAL ANATOMY. 373 

JVervous System. 

This consists of a double supra-oesophageal ganglion or 
brain (Fig. 1, b) in the head, an oesophageal collar, a sub- 
cesophageal ganglion and a row of ganglia extending along 
the median ventral part of the body cavity. The ventral 
ganglia are connected by a double commissure (nc). The 
brain gives off nerves to the ocelli, the sub-cesophageal gan- 
glion supplies the mouth parts, while from the ventral gan- 
glia nerves are distributed to the feet, prolegs and internal 
organs. 

In the caterpillar there are eleven ventral ganglia, includ- 
ing the sub-cesophageal. The posterior one is by far the 
largest, being formed by a fusion of two ganglia. During 
the pupal stage (Fig. 5) the number of ganglia is reduced 
by fusion. In the imago we find two thoracic and four 
abdominal ganglia, which are connected with the brain by 
a double commissure. 

The Fat Body. 

In its fullest development this body forms an internal 
cylinder of fat, which surrounds the alimentary canal and 
lines the body cavity of the caterpillar. It is represented 
by the dark dotted area in Plate 58, Fig. 2. It is liber- 
ally supplied with trachea? and is most prominent in well- 
fed, full-grown caterpillars. In the pupal stage (Fig. 5) the 
fat body diminishes as the reproductive system develops, the 
development of the latter taking place at the expense of 
the former. One fact, which seems worthy of record in 
this connection, is that almost no fat can be found in the 
female imago, while there is an appreciable quantity pres- 
ent in the male. Since the male is the sex that flies, this 
fat may be necessary to furnish the energy expended in 
flight. 

Reproductive System. 

This system is represented in the caterpillar by a pair of 
small reddish-brown organs (Fig. 1, ro), which lie one on 
each side of the dorsal vessel in the ninth segment. From 
these organs a pair of thread-like appendages (ducts ?) lead 



374 THE GYPSY MOTH. 

backward for a short distance. A careful sectioning of a 
single reproductive body shows it to be composed of fila- 
ments, which are coiled upon each other, forming a com- 
pact mass, which is enclosed in the external envelope. In 
the mature caterpillar, and even in those of the fourth molt, 
there is a marked difference in the structure of the repro- 
ductive organs, seemingly indicative of sexual differentia- 
tion. One form, apparently that of the female, is made up 
of medium long, thick tubes, composed of an outer wall, a 
thicker inner layer and a central lumen, which is enlarged 
at intervals, and contains in these enlargements large cell- 
like bodies surrounded by many smaller cells (nutritive 
cells?). 

That which is apparently the male form is made up of 
much smaller and somewhat longer tubes of a more nearly 
even diameter. These tubes are closely coiled on each 
other within the sac formed by the outer envelope. These 
organs increase in size as the insect approaches the pupal 
stage. Although our studies on the reproductive system 
in the pupa are not yet completed, one point is well estab- 
lished : the development of the reproductive system of the 
future imago is accompanied by a corresponding diminu- 
tion of the fat body with which the newly formed pupae 
are filled. In this stage the accessory organs and glands of 
the reproductive system are first recognizable (Fig. 5, ro). 
The reproductive organs of the male imago (Plate 59, 
Fig. 1) consist of a single button-shaped testis (t), formed 
by the fusion of the two reproductive bodies of the cater- 
pillar ; the paired seminal vessels (vs) and duct with the 
accessory glands. Four enlargements occur on each of the 
seminal vessels, two near the testis and two near the junc- 
tion of the two vessels. The last enlargement has a blunt, 
lateral projection, which receives the duct from the acces- 
sory gland. The common duct formed by the union of the 
two seminal vessels tapers for a considerable part of its 
course, then enlarges to form the seminal reservoir proper 
(sr) at the base of the penis (p), into which it discharges. 
Around the base of the penis, and attached to the lateral 
body walls, are bands of muscle fibre (m), which evidently 
serve to exsert the organ, The whole system is so compli- 



Explanation of Plate 59. 



Drawn by A. H. Kirkland. 



Reproductive system of male imago, greatly enlarged: t., 
testis; ag., accessory gland; vs., vesicula seminalis ; 
sr., seminal reservoir; m., muscle at base of penis; 
p., penis; co., Clasping organs. 

Reproductive system of female imago, enlarged: rs., recep- 
tacle of semen or copulatory pouch; od., oviduct; 
ag., accessory glands; oo., ovaries. 



•fj-iATii; oy. 




NATURAL ENEMIES. 375 

cated that no attempt has been made in the plate to repre- 
sent the various windings of the vessels and glands as they 
occur in the insect. 

The female reproductive system (Fig. 2, also Plate 58, 
Fig. 6) consists of the two ovaries (oo), each composed of 
four egg-bearing tubes, the oviduct (od) formed by the 
union of the ovarian tubes, the accessory glands (ag), and 
the copulatory pouch or receptacle of semen (rs). The 
ovarian tubes are closely coiled upon each other, and form 
an egg-mass which completely fills the body cavity. On 
the dorsal surface of the oviduct is the point of union with 
the large paired and small single accessory glands. These 
glands probably secrete the viscid coating of the eggs, which 
enables the latter to adhere in masses to the surface on 
which they may be deposited. Beneath the oviduct, and 
connected with a separate external opening, is the copula- 
tory pouch (Plate 58, Fig. 6, cp). This is a medium- 
sized pear-shaped organ, and connects with the oviduct by 
means of a slender tube. 

Natural Enemies of the Gypsy Moth. 

The birds which play so very important a part in destroy- 
ing the gypsy moth have been fully treated of in Part I of 
this work by my colleague, Mr. Forbush, and we pass to 
the consideration of the other natural enemies of the insect. 
Under these we will consider the animal and vegetable para- 
sites, the predaceous insects and other insectivorous animals, 
except the birds. 

Hymenoptera. 

In all our field operations we have endeavored, from the 
first, to learn as much as possible about our native parasites, 
and particularly to what extent they attack the gypsy moth. 
For this purpose we have paid especial attention to collect- 
ing the different species found to be parasitic upon this 
insect, and to studying their habits. The Hymenopterous 
parasites of the gypsy moth thus far found are as follows : 
Theronia melanocephala (Br.), Pimpla peddlis Cress., Pim- 
pla tenuicornis Cress. (Plate 53, Figs. 8, 8a), Anisocyrta 
sp., Diglochis oninivorus (Walk.) (Plate 53, Figs. 10, 
10a). 



376 THE GYPSY MOTH. 

The first two and perhaps the last are the most useful in 
destroying the gypsy moth, and probably are far more 
successful than the Dipterous parasites, since the latter lay 
their eggs on the outside of the caterpillars, and many of 
them are thrown off on the molted skin before they hatch ; 
while the eggs of the Hymenopterous parasites are deposited 
in the tissues beneath the skin. 

During the summer of 1895, Theronia melanocephala 
(Plate 53, Fig. 6) was the most abundant of the Hymen- 
opterous parasites, and in the larger colonies could be 
seen on warm days flying about from tree to tree, almost 
invariably alighting on the burlap bands, and even crawling 
under them in its search for pupae. In Lexington, on one 
occasion, one of these insects was seen to go from tree to 
tree until it had examined seven burlaps. After searching 
the burlaps, the trunk of the tree above and below was 
inspected, the antennse all the time being kept in constant 
motion. It has been reported that this parasite attacks 
the caterpillar when about to pupate ; but in nearly all the 
cases where its oviposition was observed this year, some 
eight or ten, the insects attacked were in the pupal stage. 
The point of attack was on the ventral surface, at the 
lower margin of the wing-cases, next the abdominal seg- 
ments. Here the chitinous integument is very thin, and 
offers the least resistance to the insertion of the ovipositor. 
When a suitable pupa is found, the parasite, after selecting 
the point for attack, curves the end of the abdomen beneath 
the body between the legs, and inserts the ovipositor into the 
pupa by a succession of movements, the whole operation 
requiring about a minute and a half. When disturbed by 
the writhing of the pupa or otherwise, the parasite with- 
draws her ovipositor and later stings again. Only one 
parasite has been reared from each parasitized gypsy moth, 
and therefore we may infer that but a single egg is deposited 
in a pupa. Mr. C. E. Bailey captured a specimen of TJier- 
onia melanocephala in the act of stinging a gypsy moth 
pupa which already contained a Dipterous maggot. Un- 
fortunately, the pupa was so crushed that it was impossible 
to ascertain what the result would have been. 

On one occasion a wood pewee was seen to snap up one 



NATURAL ENEMIES. 



377 



of these parasites, while apparently in search of pupae. 
There is no doubt that our birds which take small insects 
on the wing also destroy many Hymenopterous and Dipter- 
ous parasites. 

Pimpla pedalis (Plate 53, Figs. 7, 7a) was obtained 
from the pupae of the gypsy moth the past season, as well 
as in previous seasons, and was also bred in great numbers 
from the cocoons of the tent caterpillar (Clisiocampa ameri- 
cana) . From about two quarts of the cocoons of the latter 
insect only twenty-five moths were obtained, the rest pro- 
ducing parasites, most of which were Pimpla pedalis, though 
a few specimens of Theronia melanocephala were also ob- 
tained. Pim/pla pedalis was seen ovipositing in the cocoons 
of the tent caterpillar ; but as I have bred this parasite from 
larvte of Tortrix fumiferana received by mail, and reared 
under such conditions that it was impossible for parasites to 
approach them, I am led to believe that Pimpla pedalis, as 
well as Theronia melanocephala, oviposits not only in pupae 
but also in caterpillars. The fact that these parasites breed 
in the tent caterpillar and other insects, as well as in the 
gypsy moth, is of special interest ; for the tent caterpillars 
pupate about four weeks earlier than the gypsy moth, and the 
parasites emerge from them just in time to attack that insect, 
so that this succession of hosts favors the multiplication of 
the parasites. How these parasites pass the winter I do not 
know, but think it very probable that they hibernate as 
imagoes. Ichneumon grandis was taken in January, 1895, 
hibernating in the imago stage, in a stone wall at Swamp- 
scott, along with pupa shells of the gypsy moth and cocoons 
of Pyrrharctia Isabella. 

The following is a list of the European Hymenopterous 
parasites of the gypsy moth, some of which, however, are 
known to be hyperparasites : — 



Pteromalus halido,yanus Rtz. 

(hyper). 
Pteromalus pint Hartig. (hyper). 
Pteromalus boucheanus Rtz. 

(hyper). 
Eupelmus bifasciatus Giraud. 
Eurytoma abrotani Panz. 



Microgaster calceatus Hal. 
Microgaster (?) tenebrosus Wesm. 
Microgaster tibialis Nees. 
Microgaster (?) lipariclis Rtz. 
Microgaster pubescens Rtz. = calcea- 
tus Hal. 
Microgaster fulvipes. 



378 



THE GYPSY MOTH. 



Apanteles glomeratus L. 
Apanteles fulvipes Hal. 
Apanteles melanoscelus Rtz. 
Apanteles solitarius Rtz. 
Pimpla flavicans Rtz. 
Pimpla instigator Gr. 
31esochorus pectoralis Rtz. 
Mesochorus gracilis Brischke. 



Mesochorus splendidulus Gr. 
Mesochorus confusus. 
Campoplex conicus Rtz. 
Campoplex difformis Gr ■. = Limneria. 
Pesomachus Jiortensis Gr. (hyper). 
Hemiteles fidvipes Gr. 
Trogus flavatorius Pnz. 
Ichneumon disparis Poda. 



It is interesting to note that all the genera included in 
the above list are represented by species in this country ; 
yet, aside from the genus Pimpla, no members of the dif- 
ferent genera have been found to attack the gypsy moth. 

Predaceous Wasps and Hornets. 

The following species of wasps and hornets have been 
observed feeding upon the different stages of the gypsy 
moth: Vespa maculata Linn., Vespa consobrina Sauss., 
Vespa genua n ica Fab., Pol istes pallipes St. Farg. 

At a new colony of gypsy moths, in North Saugus, in the 
early part of August, a large number of Vespa maculata 
were observed flying close to the ground, around the base 
of the trees or carefully searching the trunks up and down, 
sometimes even going up into the tops of the trees. They 
were closely watched, and a maculata was seen to fly after a 
male moth, follow its zigzag flight as it attempted to escape, 
and finally capture and carry it to a small branch. The 
hornet soon dismembered the moth and began feeding upon 
the abdomen. 

Two other hornets of the same species were seen flying 
after male moths. The first one chased a moth up above 
the tree tops and then off to one side and out of sight. 
The other followed a moth for about eight rods through the 
woods, and then caught him, but flew ofl' before it could be 
taken with a net. 

At another time a number of large brown wasps [Polistes 
pallipes) (Plate 53, Fig. 5) were noticed flying about the 
trees. When they discovered a branch on which caterpillars 
had clustered they alighted, and, running along the under 
side of the branch and leaves, each wasp located its prey, 
left the branch, and, flying about the caterpillar, finally 



NATURAL ENEMIES. 379 

alighted upon its back, at the same time stinging- it upon 
or near the head, usually from behind. The result of this 
was to completely paralyze the caterpillar, for a time at 
least, when the wasp sucked the fluids from the body by 
cutting holes through the body wall, beginning near the 
head and working toward the posterior end. In some cases 
the wasp nearly cut the head and first or second segment 
from the body, and not unfrequently they were seen to cut 
off a part of the caterpillar and fly away with it. 

The work of the wasps was not confined to a few isolated 
cases, but they were busy every day between the hours of 
9 a.m. and 3 p.m., killing and carrying away the caterpillars. 

One of the most remarkable observations of the season of 
1895 was made by Mr. C. E. Bailey, a most careful and reli- 
able field observer. While watching the birds at Wayte's 
Mount, Maiden, for the purpose of discovering to what ex- 
tent the different species of birds destroy the gypsy moth, 
he saw a large insect seizing gypsy moth caterpillars and 
flying away with them. Being provided with a net, he suc- 
ceeded in capturing this insect while it was flying away with 
a third-molt gypsy moth caterpillar. The insect proved- 
to be the American saw-fly ( Cimbex americand) . I am not 
aware that this species has ever before been discovered to 
be predaceous in its habits, but its mandibles and other 
mouth parts are so developed that one can well believe it 
capable of predaceous propensities. 

Mr. W. L. Tower reported that on July 17, 1894, he saw 
a specimen of Tremex, or of a closely allied genus, take a 
full-grown gypsy moth caterpillar and fly away with it. As 
the insect was not captured, and under the circumstances 
could not be closely identified, we should not have con- 
sidered it worth while to mention it here but for the reason 
that it may also have been the American saw-fly, and, if so, 
a verification of the predaceous habits of that insect. An 
examination of the mouth parts of Tremex columba will con- 
vince one that this insect is not predaceous, and therefore 
the probabilities are increased that the insect seen by Mr. 
Tower was the American saw-fly. 



380 THE GYPSY MOTH. 

Ants attacking Female Imagoes. 

The following field observations show that the female 
imagoes, while laying, are often attacked and killed by 
black ants. 

Aug. 11, 1894, a female, trying to deposit an egg-cluster 
on the trunk of an oak tree, was attacked at 10.20 a.m. 
by a large black ant, which seized her antennae with its 
mandibles. The ant was captured, and the moth resumed 
laying; but at 1.40 p.m. was found in a hole in the ground, 
with a number of ants working upon her. One leg was 
gone and two more nearly severed from the body. At 2.40 
all of the legs and both antennae were missing, and the 
wings nearly destroyed. At 4.40, the thorax having been 
severed from the body and the abdomen opened from the 
anterior end, the ants commenced to carry off the egg- 
masses. 

Another female moth, while crawling in the grass, was 
attacked by the ants at 11.40 a.m., which seized her by the 
ovipositor and dragged her some distance. At 2.40 p.m. 
the ants, still at work, had torn the head from the body and 
carried it up into the tree, and soon after they opened the 
abdomen and greedily devoured the ovarian tubes. A third 
female, just beginning to lay, was seized by a large black 
ant, which dragged her to the ground, where nine more ants 
began to dissect her. The antennae and legs were removed, 
the abdomen opened, and the ants soon began feeding upon 
the egg-masses. 

To determine whether the ants will eat the eggs, the fol- 
lowing investigations were made : Four female moths were 
divested of their heads and wings, the abdomens opened so 
as to expose the egg-masses, and then placed at the base of 
four trees. In about half an hour two of the moths were 
visited by several black ants, and a short time later nine 
ants were working upon one moth. These ants feasted for 
an hour or more upon the egg-masses, with their mandibles 
closed and their heads thrust down among the eggs, as if 
sucking up the body fluids. Then they began to sever the 
thorax from the abdomen and to tear off small clusters of 
eggs, from three to seven each, and carry them with the 



PREDACEOUS COLEOPTERA. 381 

other parts of the body into their nests, in an oak tree, two 
and a half feet from the ground. When the last piece had 
been removed, the large ants left the field and were suc- 
ceeded by a smaller species, that gathered up the scattered 
eggs and minute pieces of tissue and carried them off. 
Soon the large black ants returned to another moth, and 
began carrying away masses of eggs. The smaller species 
worked upon the same insect, but were not able to make 
so much progress. In no case were the ants seen to eat a 
single egg; they only devoured the body tissues and fluids, 
particularly the ovarian tubes enclosing the eggs. Two 
harvest spiders also appeared and fed upon the egg-masses. 

Specimens of these ants were sent to Mr. Theo. Per- 
gande, who identified them as Camponotus pennsijlvanicus 
De G. (Plate 53, Fig. 9, 9a), and the large and small 
workers of Formica subsericea Say. 

In connection with the attack of ants upon the gypsy 
moth, the following note is of interest : In the early part 
of the work of trapping the male moths, in 1894, attention 
was called to the fact that in the midst of the most densely 
infested part of a grove there was a single hickory tree on 
which no egg-clusters, caterpillars or any trace of the gypsy 
moth had been found, in spite of the fact that the trees and 
shrubs almost touching it on every side were all found to 
be badly infested. The tree in question was inhabited by 
small black ants, in fact, was full of them, and to these 
probably owed its escape from the ravages of the gypsy 
moth, while other trees of the same species, not inhabited 
by ants, were infested. The larger species of black ants 
have also been seen feeding on dead caterpillars and pupae 
of the gypsy moth. 

Predaceous Ooleoptera. 
Several species of beetles have for some time been known 
to destroy the gypsy moth. On the 20th of May, 1892, 
Mr. C. H. Rowe found the fiery hunter (Calosoma calidum) 
devouring the young gypsy moth caterpillars at the base of 
an oak tree in Maiden. The beetle was captured, and sub- 
sequently liberated in a breeding cage containing thirty-six 
full-grown caterpillars, and others were added as they were 



382 THE GYPSY MOTH. 

needed. In five days ninety-three caterpillars were de- 
stroyed, only portions of the larval skins remaining. The 
beetle was fed for two weeks with various species of cater- 
pillars and the larvae of leaf-eating beetles. There seemed 
to be no choice made of the different species of caterpillars 
supplied, but all were in due time attacked and more or less 
eaten. From the number of caterpillars eaten in the five 
days, Mr. Rowe estimates that the average daily consump- 
tion of this beetle is about equal to six full-grown gypsy 
moth caterpillars. Mr. Rowe also reports the larvte of two 
species of Harpdlus feeding on young gypsy moth cater- 
pillars. 

For the purpose of ascertaining more fully the habits of 
the predaceous beetles, the following species were observed 
in confinement, in the insectary at Maiden, during the sum- 
mer of 1895, and later they were confined and fed in cages 
out of doors. One specimen of Calosoma scrutator was 
brought in June 28, and put into a cage with ten gypsy 
moth caterpillars, which were at once attacked by the beetle. 
The favorite place of attack seemed to be the middle of the 
body. As the viscera of the caterpillar came out the beetle 
chewed away steadily, apparently seeking the fatty parts. 
In two days fourteen caterpillars were eaten. At the end 
of this time the beetle was placed in a cage with another 
individual of the same species. July 1, the two beetles 
killed seven gypsy moth caterpillars, and eleven more were 
put in the cage. The next day ten were dead, and ten more 
of the fourth and fifth molt were put in. One caterpillar 
pupated, and the pupa was destroyed by the beetles. July 
3, six caterpillars were killed, and eight more of the fourth 
and fifth molt were put in. July 4, one of the beetles died. 
The remaining beetle killed four caterpillars July 5, but 
died on the next day, after killing two more caterpillars. 
These two beetles killed, in all, thirty-six gypsy moth 
caterpillars. 

Another individual of this species was placed in a cage 
July 2, and kept supplied with gypsy moth caterpillars. 
July 18, another beetle of the same species Avas placed in the 
cage and supplied with food. The first beetle, during the 



PREDACEOUS COLEOPTERA. 383 

fifteen days before the second was put in, destroyed thirty- 
one caterpillars and three pupte ; and, after the other beetle 
was put in with it, the two destroyed fifty gypsy moth 
caterpillars and one Sphinx drupiferarum caterpillar before 
July 24, when the first beetle died. The remaining beetle 
destroyed four gypsy moth caterpillars, one sphinx cater- 
pillar and one male gypsy moth between July 24 and July 
30. Another Calosoma scrutator was then put into the cao-e, 
and August 5, when they were placed out of doors, they had 
killed eight caterpillars, three pupseand two female moths. 

Two specimens of Calosoma frigidum (Plate 53, Fio-. 
1) , male and female, were put into a cage together at the in- 
sectary, June 28, and supplied with gypsy moth caterpillars. 
This species is much smaller and more active than C. scru- 
tator. They are not so clumsy, but are able to seize the 
caterpillars and destroy them while on a vertical surface, as 
on the trunk of a tree. July 27, one of these beetles died, 
and the other was removed to be used by the artist. Dur- 
ing this time they killed ninety-two gypsy moth caterpillars, 
three pupae and one female moth. 

Three other individuals of this species were put into a 
cage in the insectary, July 21, and supplied with gypsy 
moth caterpillars. One of the beetles died the second day, 
and on August 5 the other two were placed in an outside 
cage. During the fifteen days that these beetles were fed 
in the insectary they killed thirty-nine gypsy moth cater- 
pillars, two pupae, two sphinx caterpillars and one cut- 



worm. 



Calosoma calidum. — Three specimens of this beetle were 
placed in a cage July 12, and supplied with gypsy moth 
caterpillars. July 19, twenty-three caterpillars had been 
killed, and another beetle was put into the cage. July 27, 
one of the beetles died, the four having killed thirty-four cat- 
erpillars and one pupa since July 19. Fifteen gypsy moth 
caterpillars, four pupae, eight cut-worms and two Sphinx 
drupiferarum caterpillars were killed between July 27 and 
August 5. 

One specimen of Carabus serratus was supplied with 
gypsy moth caterpillars, and killed five before it died. 



384 THE GYPSY MOTH. 

Platynus limbatus was also found feeding on pupae in the 
field, but it would not feed upon them in confinement. 

For the purpose of keeping and feeding some of our pre- 
daceous beetles, under as natural conditions as possible, 
Mr. Kirkland very ingeniously arranged a number of cages 
(Plate 60), and attached them to the trunks of trees in the 
woodland near the insectary. These cages were of wire 
netting, bent into a nearly cylindrical form. The edges 
were fastened to the two sides of the tree trunk, the lower 
end extending down into the ground and the upper end 
covered by a piece of cloth, one side of which was secured 
to the tree, the other covering the top of the wire screen 
cage, and held in place by a rubber strap, the ends of which 
were fastened to the trunk of the tree. This rubber band 
could easily be removed from the top of the cage and the 
cloth lifted sufficiently to give free access to the interior. 
A few small stones and some moss were so arranged on the 
ground, at the bottom of the cage, as to furnish hiding- 
places for the beetles. Each cage had a tag attached to it, 
on which was the number and other necessary data. 

Two specimens of Calosoma scrutator were placed in cage 
No. 1, August 9, and supplied with gypsy moth caterpillars. 
August 20, fourteen caterpillars had been killed. 

Five specimens of Calosoma frigidum and one of Calo- 
soma calidum were put into cage No. 2, August 9, and 
supplied with caterpillars. One specimen of C. frigidum 
died August 13, and August 20, twenty-five caterpillars had 
been killed by these beetles. 

Ten specimens of Harpalus caliginosus were put into cage 
No. 3, August 9, and supplied with caterpillars, and August 
20, twenty-two of these caterpillars had been destroyed by 
the beetles. 

Ten specimens of Harpalus jpennsylvanicus were placed 
in cage No. 4, August 9, and furnished with caterpillars ; 
August 20, twenty-three caterpillars had been killed by the 
beetles. 

During the summer of 1891, Mr. E. P. Felt obtained a 
specimen of Dermestes lardarius from a mass of gypsy moth 
pupae. 



PARASITIC DIPTERA. 385 

Several Coleopterous larvie have been found feeding upon 
the egg-clusters of the gypsy moth, but we have been unable 
to obtain the imagoes from them. During the past year 
Mr. C. H. Rowe succeeded in rearing a specimen of Ptinus 
brunneus from a gypsy moth egg-cluster. 

The following species of predaceous beetles are said to 
attack the gypsy moth in Europe : — 

Calosoma sycophanta (L.) (larva). 
Tiresias serra (Fab.) (eggs). 
Dermestes ater (Panz.) (eggs and pupas). 
Dermestes lardarius (L.) (eggs and pupae). 

Diptera. 

In June, 1891, while on a visit to the territory infested 
by the gypsy moth, my attention was first called to the fact 
that flies were depositing their eggs on the caterpillars ; and 
since that time the field workers have reported these para- 
sitic flies in no less than ten towns, showing that they 
probably occur throughout the entire infested region. The 
number of these eggs on a single caterpillar was reported 
by twelve different inspectors who observed them, as vary- 
ing from one to twenty, though some state that they have 
seen the caterpillars " nearly covered," and others " eggs in 
great numbers on them." Directions were then given to 
collect and rear the parasitized caterpillars till these para- 
sites should emerge. It was found that many of the cater- 
pillars molted their skins before the eggs of the parasites 
hatched, and therefore comparatively few of them were able 
to make their way into their insect hosts and destroy them. 
If the caterpillars had not molted before the eggs of the 
parasites hatched, their destruction would have been vastly 
greater. During the summer of 1893, Mr. Reid collected a 
number of caterpillars on which the eggs of the parasites 
had been laid. Two hundred and thirty-five of these cater- 
pillars, having from one to thirty-three eggs on them, were 
fed in cages until they changed to pupte ; and from these 
two hundred and twenty-six moths emerged, but only four 
Dipterous parasites were secured from this entire number. 
The caterpillar which had thirty-three parasite eggs on it 



386 THE GYPSY MOTH. 

when brought in molted before these eggs hatched, passed 
all its transformations, and the moth emerged from it in 
good condition. 

In July, 1895, a careful examination was made to deter- 
mine the proportion of caterpillars in the field that had the 
eggs of the Dipterous parasites attached to them. July 3, 
live trees were examined in Dorchester, and 2,200 cater- 
pillars were found, 500 of which had the eggs of parasites 
on them. July 8, six trees were examined in Medford, and 
1,847 caterpillars found, 397 of which bore parasite eggs. 
The total number of caterpillars examined was 5,547, of 
which 1,597, or nearly 29 per cent., had the eggs of Dip- 
terous parasites attached to some part of the body. 

Several Dipterous parasites were bred, during the summer 
of 1895, from infested pupae, the majority of which pro- 
duced only one parasitic fly, while a few produced two. 
Many parasitized pupae contain maggots which have not yet 
pupated. The vitality of these Dipterous parasitic larvae is 
very remarkable. One of them was placed in a twenty per 
cent, solution of formol at night, August 15, and twenty- 
four hours later it was found swimming around, apparently 
uninjured. The larva was at once removed from its formol 
"bath," and was still living October 1, but had not pupated. 
In several cases where two larvae were found in a small pupa 
of the gypsy moth, and there seemed an insufficient amount 
of food for them, a large female pupa was cut open and a 
parasite larva placed on the cut end of each half. They at 
once burrowed into the tissues and fed there several days. 
One larva ate the substance of six female pupae in this way 
before reaching its full growth. 

Fifty gypsy moth caterpillars, having eggs of a Dipterous 
parasite on them, were collected in Dorchester, June 21, 
1895, and carefully bred in separate boxes. The eggs were 
deposited without regularity on nearly every part of the 
body. Forty-three of these caterpillars passed their trans- 
formations, producing perfect moths, six males and thirty- 
seven females ; while seven died, but not because of the 
parasites, for the caterpillars had -all molted before the eggs 
of the parasite had hatched. Two hundred and fifty-two 



PAKASITIC DIPTERA. 387 

other caterpillars taken in the field, and bearing Dipterous 
e«gs, were fed and carried through their transformations 
with the same result as in the case cited above. 

All the Dipterous parasites bred from the gypsy moth, 
and also those collected in 1891, were sent to Dr. S. W. 
Williston for determination. They were determined by 
him as follows : — 

Exorista, two species; Phorocera, four species. These 
are true parasites. 

• Gaurax anchora Loew, whose larvre had been observed 
by Osten Sacken in multitudes upon the pupse enclosed in 
the cocoons of the Cecropia moth ; Phora scalaris Loew ; 
Phora incisuralis Loew, var. The last three species are 
regarded by Dr. Williston as accidental parasites entering 
the pupos of the gypsy moths while the flies are in the larval 
state, and then feeding in and destroying the moths. 

Sarcqphaga, two species. Schiner expresses very grave 
doubts whether the species of Sarcojihaga ever feed on any- 
thing but dead animal matter, while Brauer states that their 
larvae are sometimes parasitic. 

Cyrtoneura stabulans Fall. According to Hartig and 
Bremi, the larva of this species is sometimes found in the 
caterpillars of certain Bombycid moths. 

In 1894, I sent another lot of Diptera bred from the gypsy 
moth to Dr. "Williston for determination, and in reply he 
wrote as follows : "I send you herewith the manuscript on 
the Diptera sent me, except a portion of that formerly sent 
to you, the specimens of which have got mislaid or rather 
lost in the general collections, and have not yet been found. 
There were several specimens, how many I do not know, 
but not including the Tachinids which I had separated out." 
Should the above-mentioned species be found, there may 
prove to be something of interest to add to our list. Dr. 
Williston kindly sent the following descriptions for publi- 
cation in this report : — 

Achcetoneura fernaldi n. sp. (Plate 53, Fig. 11, a-e.) 
Male. — Frontal stripe deep brown, a little narrower than 
the sides of the front; sides light golden yellow, reaching 
a little way on the sides of the face. At each angle of the 



388 THE GYPSY MOTH. 

eye there is a stout bristle curved backward ; on either side 
of the frontal stripe a single row of bristles, of which the 
two uppermost are stronger than those before them, and are 
curved backward. The frontal row extends down on the sides 
of the face for a short distance beyond the base of the an- 
tennas and to nearly opposite the uppermost bristle of the 
facial row ; the proclinate ocellar bristles moderately strong. 
Antennas wholly black, the third joint but little more than 
three times the length of the second joint. Face satiny 
white ; vibrissal bristles situated a little distance above the 
oral margin ; above them is a row of not very strong bristles 
extending about midway to the root of the antennas. Sides 
of the face wholly bare, except for the previously mentioned 
bristles. Cheeks covered with short, black, bristly hairs, 
their length equal to about half that of the eyes. Eyes 
wholly bare. Palpi yellowish. Mesonotum shining blue 
black, with inconspicuous stripes. Scutellum broadly red- 
dish on the apex, the apical pair of bristles small and decus- 
sate. Abdomen shining blue black, with a broad, variable, 
white pollinose, basal band on the segments ; first and 
second segments each with a pair of marginal bristles ; 
third segment with a posterior row ; the general covering 
of the abdomen is composed of rather stout bristly hairs, 
which are more abundant, longer and intermixed with finer 
hairs distally. Legs wholly black, the front femora whitish 
pollinose behind ; pulvilli much elongated ; the claws elon- 
gate and slender. Wings grayish hyaline ; third vein with 
a few short bristles at the very beginning ; angle of the 
fourth vein without a stump, though with a fold appearing 
somewhat like one. 

Female. — Differs from the male in the front being wider, 
in the presence of two proclinate orbital bristles on each 
side, in the abdomen being less hirsute and in the short 
claws and pulvilli. Length of male, 10 mm. ; of female, 
12 mm. 

Twenty-five specimens from Professor Fernald, labelled 
as follows : ' < From larvas which died in parasitic cage 
Aug. 27 (male), 28 (male and female), 29 (male), 1893, 
laboratory Gypsy Moth Department, Maiden." " Emerged 



PARASITIC DIPTERA. 389 

from pupa of P. dispar Aug. 22, 1893 " (female) ; and 
"Emerged from gypsy moth pupae Aug. 24 (male), 27 
(female), 29 (female), 1891; Sept. 2 (female), 1891." 

I have compared these specimens with a female type of 
A. (Masicera) frenchi Williston, with which the species is 
closely allied, and find the following differences : The facial 
bristles ascend higher in A. frenchi, reaching two-thirds or 
more of the distance to the root of the antenna?, while in 
A. fernaldi they do not go more than half way, and some- 
times even less than that. The bristles of the front do not 
descend so far as in A. frenchi. But the chief difference, 
and one by which the species will be readily recognized, is 
the relatively much shorter third joint of the antennae in the 
present species. In A. frenchi it is fully five times the 
length of the second. The marginal bristles of the abdo- 
men seem to be stronger in A. frenchi. In the type female 
compared there are none on the first segment, but I suspect 
that the species has them normally. 

From Achcetoneura (Masicera) sphingivora Towns., Trans. 
Am. Ent. Soc, Vol. XIX, page 286, the length of the 
antennae and the red sides of the abdomen are sufficient 
to distinguish. From A. (Masicera) euftchice Towns, the 
differences are also evident. 

Sarcqphaga, sp. Female. — Sides of the front and face 
wholly silvery white ; median frontal stripe black. Antennae 
black, third joint between three and four times the length 
of the second joint. Abdomen black, silvery white, mar- 
morate ; fourth segment wholly black. Legs black, the 
hind tibiae not ciliate. Palpi black. Length, 12 mm. 

One specimen, labelled "From parasitic material, Aug. 
1, 1893, Gypsy Moth Department, Maiden." The single 
specimen is not in the best state of preservation, and it is 
difficult, if not impossible, to either identify it with any 
previously described species or to give a description which 
will enable the species to be again determined with cer- 
tainty. The diagnosis given above wil serve to exclude all 
but nearly related species. 

Gyrtoneura stabulans. — Musca stabulans Fallen. Mei- 
gen, Schiner (Gyrtoneura), etc. Europe, New Zealand, 
North America. 



390 THE GYPSY MOTH. 

Female. — Front a little less than one-third of the width 
of the head, gray pollinose on the sides, the median stripe 
deep reddish brown or black, broader than the sides, nar- 
rowed below ; a pair of proclinate ocellar bristles pres- 
ent ; the lateral row of bristles has an outward curvature. 
Second joint of the antennas reddish ; in front somewhat 
blackish, and with erect bristles ; third joint black, about 
three times the length of the second; arista thickened at 
the base, plumose. Sides of the face narrow, bare. Cheeks 
in width about equal to the length of the third joint of the 
antenna?, with a row of bristles on the inferior margin 
reaching to the moderately stout vibrissas a little above the 
oral margin ; bare on the upper part, and with short bristly 
hairs below. Sides of the face and the upper part of the 
cheeks reddish in ground color, covered with silvery pubes- 
cence. Mesonotum gray pollinose, variable, with four nar- 
row, shining black stripes, the lateral ones interrupted. 
Scutellum broadly reddish at the apex ; apical bristles long, 
decussate. Abdomen uniformly covered with gray pol- 
len, moderately variable in different reflections, the ground 
color everywhere shining black. Legs yellow; the front 
femora in large part and the base of the middle femora 
black ; all the tarsi blackish. "Wings grayish hyaline ; first 
posterior cell only a little narrowed at the tip ; penultimate 
section of the fourth vein shorter than the antepenultimate 
section. Length, 6-7 mm. 

Three specimens, labelled "Emerged from gypsy moth 
pupo?, Aug. 20—21 and 25, 1891." This species is the one 
which I have commonly identified as C. stabulans Fall., but 
I have never compared it directly with European specimens. 
According to Schiner, it has been bred from Bombyx pyri 
and Lophyrus, and also from various species of Boletus. 

Elacliiptera dispar n. sp. (Plate 53, Figs. 12 and 12a.) 
Female. — Head yellow, a minute spot at the ocelli and the 
arista black. Thorax light yellow ; a narrow median stripe 
extending from the front margin of the mesonotum to the 
tip of the scutellum ; a small oblique spot on each side, 
contiguous with the front end of the stripe, and the disk of 
the mesonotum, black. Abdomen yellow ; second segment, 



PARASITIC DIPTERA. 391 

except a broad triangle whose apex reaches the hind mar- 
gin, and all of the following segments, black. Legs light 
vellow ; the front tibiae and tarsi brown, the other tarsi 
brownish. Wings cinereous hyaline. Length, 2 mm. 

Two specimens, labelled "Emerged from gypsy moth 
pupse, Aug. 21, 1891." The arista has been broken away 
in both specimens, save the basal part ; this part, however, 
is so thickened and pubescent that I believe that I am not 
in error in referring the species to Elachiptera (Cntssiseta) , 
where it finds its nearest ally in E. eunota Loew. 

Phora setacea Aldrich, Can. Ent., Vol. 24, page 144, 
Brookings, South Dakota (reared from Cimbex americaTia). 

Notwithstanding the difference of locality and habits, I 
believe that the specimens bred from the gypsy moth par- 
asitic material and sent to me by Professor Fernald are of 
the same species as those described by Professor Aldrich. 
I have only males, and it is possible that the females may 
show some discrepancies. The specimens differ from the 
description only in the male genitalia, which do not have 
the projecting abdominal segment as described, and in the 
first weak vein of the wings, which is distinctly curved and 
not " almost straight." The species will be best recognized 
by the arrangement of the lowermost frontal bristles, for 
the position of which the reader is referred to the figure and 
description given by Aldrich. Otherwise the species may 
be briefly described as follows : — 

Male. — ■ Head black, antennae fuscous ; palpi yellow, with 
black bristles ; proboscis yellow. Thorax black. Abdomen 
black ; halteres light yellow. Front and middle legs yellow, 
the hind ones more brownish. One spur at the tip of the 
tibiae, save of the front pair, where there are none. Wings 
hyaline; second heavy vein (third longitudinal) furcate; 
bristles on costal border long. Length, 1.5 mm. 

It is probably true that the species of Phora are not truly 
parasitic, but live in any dead or decayed material that 
comes in their way ; still, it is not certain but that they may 
attack the living insect. 

The following list of the European Dipterous parasites 
of the gypsy moth has been compiled from various sources. 



392 



THE GYPSY MOTH. 



Many of the names are taken from a list furnished me by 
Dr. S. W. Williston : — 



Exorista lucorum Meig. 

Exorista (Myxexorista) libatrix 

Panz. 
Exorista erythrostoma Hrtg. 
Parexorista sussurans Kond. 
Meigenia bisignata Schin. 
Tachina bella Meig. 
Tachiua pinivora Ratz. 
Tachina larvincola Ratz. 
Tachina monacha Ratz. 
Tachina noctuarum R. D. 
Tachina quinquevitala Hrtg. 
Tachina rustica Fall. 
Tachiua larvicola Hrtg. (?) 



Tachina moreti R. D. 

Tachina (Echiuomyia) conjugata 

Bond. 
Tachina (Echinomyia) fera L. 
Tachina bimaculata Hrtg. 
Eutachina larvarum L. 
Phorocera concinnata Meig. = M. 

serrieventris Rond. (?) 
Sarcophaga affinis Fall. 
Thelymorpha vertiginosa Fall. 
Argyrophylax gilva Hrtg. 
Parasitigena segregata Rond. 
Macharasa serriventris Rond. 
Choetoniyia crassiseta Rond. 



It will be observed that the single species of Tachinidce 
thus far known to infest Porthetria dispar, in North 
America, belongs to a different genus, or sub-genus, from 
any in the above list, all of which are Tachinids except one. 
It Avill be of interest to determine the earlier or normal host 
of A-chcetoneura femaldi. 

Predaceous Diptera. 

Of the predaceous Diptera the following species have 
been taken feeding upon the imagoes of the gypsy moth : 
Dasyllis sacrator Walk., attacking the females while laying ; 
Asilus sericeus Say, capturing the male imagoes on the 
wing. 

Predaceous Hemvptera Ileteroptera. 

The following account of the predaceous Hemiptera Heter- 
optera, known to feed on the gypsy moth, has been prepared 
for this report by A. H. Kirkland, B.Sc, assistant entomol- 
ogist. 

An important factor in the destruction of the gypsy moth 
caterpillars is the aid rendered by several species of pre- 
daceous bugs, which, in badly infested localities, attack the 
caterpillars in considerable numbers, and in some places 
apparently feed upon them in preference to any other kinds 
of Lepidopterous larvae. The predaceous bugs thus far found 
feeding upon the gypsy moth are Podisus cynicus (Say), 



PREDACEOUS HEMIPTERA. 393 

P. serieventris Uhl. and Menecles insertus (Say). Perillus 
circumcinctus Stal. has also, this year, been doubtfully re- 
corded, in a single instance, as attacking gypsy moth cater- 
pillars. The following pages present the facts we have 
ascertained concerning the habits of each species, together 
with the life history of P. serieventris. 

General Habits. — All these species appear to be arboreal 
in habits, although they are occasionally taken on the ground. 
Their chosen food in this region seems to be the caterpillars 
of the different Lepidoptera, and in the search for them the 
bugs often climb trees to a great height. The bugs seek 
out caterpillars in their hiding-places in the rough bark, or 
even follow them to their feeding-places on the foliage, and 
attack them both during the day and at night. These pre- 
daceous insects possess a considerable degree of activity, 
most noticeable on warm days, and have also the ability to 
exist for some time without food, especially in the earlier 
stages. During the present summer, at the insectary, speci- 
mens of P. serieventris were found to be alive and fairly 
active at the end of five days from hatching, without once 
having taken food. This marked degree of vitality of the 
young bugs is perhaps not surprising, since from the time 
of hatching to the time of first feeding, the element of chance 
enters most strongly into their career, for they may often, 
of necessity, travel over a large part of a tree before 
finding food for the first time. These species are found on 
all parts of the trees, and, while they are more or less gre- 
garious in the first and second stages, in the later stages 
they usually feed independently of each other. I have re- 
peatedly seen the imagoes of P. serieventris fly short dis- 
tances, which would indicate that this is its ordinary mode 
of transit from one tree to another. This latter species 
shows a considerable attraction to light. 

Of the three species mentioned, M. insertus seems to be 
the most local in its distribution in the infested district. 
In the restricted areas in which it occurs it is fairly abun- 
dant, but its limited distribution in the territory infested by 
the gypsy moth renders it of less importance than P. cynicus 
or P. serieventris. The two latter species are very gener- 



394 THE GYPSY MOTH. 

ally distributed throughout the infested region, and the 
good they do in destroying the caterpillars of this insect is 
of no little importance. The larger of the two species, 
P. cynicus, occurs in smaller numbers than P. serieventris, 
and, although it will destroy more caterpillars during its 
feeding season, jet from the moderate numbers in which 
it occurs it is not so valuable an ally as P. serieventris. 
Whether these insects are devoured by birds to any great 
extent I am unable to state. The odoriferous glands with 
which they are provided would seem to be a means of pro- 
tection against their natural enemies. A pair of crows, 
confined at the insectary, devoured all specimens offered 
them of the three species of these bugs, and Mr. Forbush 
informs me that in nature these insects may possibly be 
destined to some extent by crows, since these birds are 
known to include the Heteroptera in their bill of fare. 

Method of rearing Predaceous Bugs. — The problem of 
breeding any Heteropterous insect presents at the outset 
many difficulties, and but little assistance is given by the 
literature on this sub-order of insects. Concerning this sub- 
ject, Douglas and Scott, in their work on " British Hemip- 
tera," Vol. I, page 5, 18G5, wrote: "It is probable, in 
consequence of the fact that the Hemiptera-Heteroptera are 
in all stages of their existence active and suctorial, and the 
consequent difficulty of supplying them, in confinement, with 
fresh, appropriate food, that but few observations upon their 
natural history have been recorded. . . . But, whether 
each species casts its skin the same number of times ; how 
long the individuals of each species remain as larva, pupa 
or imago ; what species have more than one brood in a 
year, and what constitutes the food of each species, — are 
matters that, in the great majority of instances, remain to 
be determined. There is, therefore, a wide field for re- 
search in the natural history of this sub-order of insects." 

While considerable has been done toward gaining a 
knowledge of the life histories of many of our plant-feeding 
Heteroptera, in the thirty years which have elapsed since 
the above was written, as yet we know but little of the life 
history of those members of the family which are predaceous 



PLATE 61. 





FIG. 1. (XT2) 



FIG. 2. (X12) 





FIG. 6. <X6) 



FIG. 3. Ixa) 






Kirkland 



FIG. 9. (X5) 



FIG. 10. 

SUFFOLK ENG. CO. 



Explanation of Plate 61. 



Drawn by A. H. Kirkland. 



Podisus serieventris Uhl. 

i. Egg. 

2. Newly hatched nymph. 

3. Nymph after first molt. 

4. Spiny armor on surface of egg, greatly enlarged. 

5. Curved spine from upper part of egg, greatly 

enlarged. 

6. Nymph after second molt. 

7. Antenna of nymph. 

8. Tarsus of nymph. 

9. Nymph after third molt. 

10. Out-door cage used in rearing this species. 



PREDACEOUS HEMIPTERA. 395 

upon other insects. The first stumbling block met with, in 
attempting to raise these insects, was the provision of a 
suitable breeding-cage, and many attempts made, both dur- 
ing 1894 and 1895, to breed them in confinement in boxes, 
jars, etc., gave only negative results. With the establish- 
ment of an insectary at Maiden and increased facilities for 
out-door experimentation, in June, 1895, other attempts 
were made to construct a cage in which one might rear 
these insects under the nearest possible approach to natural 
conditions. After several experiments a breeding-cage was 
devised which gave the desired result (Plate 61, Fig. 10). 
This consists of a fine wire gauze, semi-ellipse, fastened 
tightly at the sides to a small tree trunk, and closed at the 
bottom by a tight-fitting wooden base, the cage, on the 
whole, being quite similar to those used in rearing the pre- 
daceous beetles. The top is covered by a piece of cloth, 
held firmly in place by a rubber band, while a small wooden 
hoop is placed around the inside of the top of the cage, in 
order to prevent the band from pulling the cage out of 
shape. The cages used are twelve inches in height by 
four inches in width, the maximum distance of the outer 
part from the tree being five inches. In cages like the one 
described the bugs were fed on Lepidopterous larvae and 
reared through their different stages. For many careful 
notes on the feeding habits of these insects I am indebted 
to Mr. H. L. Frost, who assisted me in the work. In 
these cages we were able to successfully carry specimens of 
P. serieventris through all their transformations. 

Life History of P. serieventris TJld. 
The Egg. — The eggs have been found deposited in small 
clusters on the bark of trees, on leaves and on the burlap 
bands. When first laid they are of a glistening, whitish- 
gray color, but this soon changes to a bronze, which grows 
darker as the embryo develops, up to within about a day 
previous to hatching. At that time the eggs grow lighter 
in color, possibly due to the entrance of air into the shell. 
Each egg-cluster contains from ten to thirty eggs, two or 
three clusters being laid by each female. The eggs (Plate 



396 THE GYPSY MOTH. 

61, Fig. 1) are ovoid, .9 mm. in length and .8 mm. in 
width. The smaller end of the eo-o- is attached to the sur- 
face on which the cluster is deposited. At the top of the 
egg is a well-defined circular cap. The greater part of the 
surface of the egg is covered by irregular rows of minute 
short spines (Plate 61, Fig. 4), nearly absent at the base 
of the egg, while around the circumference of the cap is a 
row of long, slightly curved capitate spines (Plate 61, Fig. 
5), arranged in a circle. The eo^s hatch in about eight 
days. Four lots of eggs kept at the insectary hatched in 
seven, eight, eight and nine days respectively. In hatching, 
the circular disk at the top of the egg is pushed back, but 
usually remains attached at one point. 

First Stage. — The newly hatched bug (Plate 61, Fig. 2) 
is 1.5 mm. in length. Form, ovate, head, thorax and abdo- 
men distinctly separated. Head smooth, broadly elliptical, 
wider than long, of a deep copper color, and sparsely clothed 
with short, pale-brown hairs ; eyes large, projecting later- 
ally. Antenna3 1 mm. long, four-jointed, of the same color 
as the head, but lighter at the joints, and clothed with a few 
hairs. The basal joint is stout, slightly curved outward; 
the second and third joints are of the same length as the 
basal, and each is enlarged at its outer end, which is quite 
sharply truncate. The fourth joint is from one-fourth to 
one-third longer and wider than the other joints, being quite 
broadly dilated. The thorax is of the same color as the 
head, and widened posteriorly. A faint sulcus, indicated 
by a narrow line, extends from the centre of the head down 
the dorsal line of the thorax to the abdominal segments. 
Abdomen yellowish red, varying to vermilion. On the dor- 
sum of the abdomen are three large, dark, bronze-colored 
spots, extending transversely, and separated by a narrow 
line of the body color. A short, narrow line of the same 
color as the spots sometimes occurs in front of the anterior 
spot, and also immediately behind the posterior one. 
Around the lateral margin of the abdomen on each side is 
a row of semi-elliptical bronze-colored spots. Just ante- 
rior to the first of these spots is a narrow, wedge-shaped 
marking of the same color, while at the extreme posterior 



PR.EDACEOUS HEMIPTERA. 397 

end of the abdomen is a larger horizontal spot, which covers 
the anal segments and often connects the two posterior 
lateral spots. The under surface of the body is yellowish 
red, darkest on the abdominal segments. The lateral row 
of semi-elliptical spots, similar to those upon the upper sur- 
face, extends around the entire margin of the abdomen. 
Beak stout, four-jointed. Both beak and legs are of a dark 
copper color. Tarsi two-jointed ; claws simple, two in num- 
ber, light brown, each with a darker pul villus ; legs sparsely 
clothed with pale-brown hairs. 

The first molt takes place in about four days from the 
time of hatching, and is accompanied by a marked increase 
in size. 

Second Stage. — The second stage of this insect is repre- 
sented on Plate 61, Fig. 3. Length, 3.5 mm. ; body a little 
longer in proportion to the width than in the first stage ; 
head quadrangular, with two faint sulci, extending backward 
from the anterior margin for about one-third of the length 
of the head. Eyes prominent. Basal joint of antennae short 
and stout ; second joint cylindrical, truncate at the end, twice 
as long as the basal joint ; third joint slightly longer than 
basal joint, and somewhat rounded at the outer end; fourth 
joint appressed at each end, and of nearly the same length 
as the second joint. The thorax is slightly serrate around 
the outer margin, and its outer angles project by the base 
of the head for a short distance. The color of the head and 
thorax is dark seal brown, varying to a pitchy black. Ab- 
domen of the same color as in the preceding stage, but 
with four horizontal spots instead of three, the second and 
third spots being much larger than the first and fourth. 
Lateral spots as in the first stage. The under surface of 
the head and thorax is marked with dark brown, that of the 
abdomen being the same color as in the preceding stage. 
Beak and legs dark brown, lighter on the tarsi. 

The second molt, with an accompanying increase in size, 
takes place from eight to ten days after the first molt. 

Third Stage. — The third stage is represented by Plate 
61, Fig. 6. Length of body, 6 mm. ; form somewhat ovate, 
narrowest in front. The head is narrowed from that of the 



398 THE GYPSY MOTH. 

preceding stage, and the eyes are very prominent. Antennas 
as in the second stage. The outer anterior angles of the 
head are rounded, as well as that part of the anterior margin 
included between the two sulci ; the latter extend backward 
about one-third the length of the head. The outer margin 
of the thorax is serrated, as in the preceding stage. The 
color of the body in this stage is subject to great variation, 
but brown or black predominates upon the head and thorax 
and some shade of red upon the abdomen. Usually the head 
and thorax are margined with a narrow, pale-yellowish-white 
line, while four small spots of pale-yellowish brown occur 
on opposite sides of the dorsal line of the pro-thorax, and 
two spots of the same color on each side of the dorsal line 
of the meso-thorax. The abdomen bears the same markings 
as in the preceding stages, but the ground color varies to a 
considerable degree. From each side of each dark marginal 
spot a creamy-white line extends in towards the large dorsal 
spots. In some cases these lines are very wide, and give to 
the abdomen a very light and somewhat striped appearance ; 
in other cases they are nearly obscured by the red ground 
color. The beak, legs and under surface of the body are 
marked the same as in the second stage. As the nymph of 
the third stage approaches the molting period, the outlines 
of the scutelluni and wing pads become somewhat apparent. 
The third molt occurs from five to six days after the pre- 
ceding one. 

Fourth Stage. — This stage is shown on Plate 61, Fig. 9. 
Length of body, 8.5 mm. General form of body, aside from 
head, nearly elliptical, slightly widened posteriorly. Head 
with two deep sulci, and closely appressed to the anterior 
margin of the thorax. Antennas as in the preceding stage, 
the second joint much the longest. The yellow marginal 
band of the head and thorax is wider than in the third stage, 
otherwise the colors of the upper surface of the body are the 
same as those of the third stage. The under surface of the 
body sometimes varies to a brownish tint, but in general it 
is like that of the preceding stage. The color of the legs 
and beak is not changed from that of the third stage. The 
wing pads and scutellum appear in this stage. Nymphs in 



PREDACEOUS HEMIPTERA. 399 

the fourth stage show great rapacity, and a corresponding 
growth is made. 

The fourth and last molt takes place in from twelve to 
seventeen days from the third molt, and the insect attains 
the imago form. 

Fifth Stage, or Imago. — The following is Professor 
Uhler's original description of this species, taken from 
"Proceedings of the Boston Society of Natural History," 
page 94, Vol. XIV., 1870: — 

" P. serieventris, n. sp. Similiar to P. modestus Dallas, 
but of a more blackish-gray color. Pronotum, sides less 
deeply sinuated, the humeral angles not so prominent, ob- 
tusely triangular, blackish ; the surface less regularly punct- 
ured, those each side anteriorly and in the corners finer, 
confluent, presenting the appearance of four blackish spots, 
the middle surface somewhat bald, yellow. Scapus and basal 
joint of the antenna? blackish outwardly. Scutellum punct- 
ured with black, the punctures at the base aggregated in a 
large patch, the basal angles with a large, smooth, whitish 
spot, the tip smooth, white. Pectus remotely punctured 
with fuscous, the impressed portion of the propleura, the 
middle of the mesopleura and exterior part of the metapleura 
with a large patch of black, confluent punctures, the exterior 
margin smooth ; exterior end of the osteolar duct black, the 
sulcus broad, not reaching to the tip. Legs pale orange 
yellow, the femora pointed with black, the dots more or less 
aggregated beyond the middle. Corium less coarsely punct- 
ured, the punctures fuscous or rufous ; those of the costal 
area coarser, the finer ones aggregated in small patches ; 
the surface adjoining the inner surface and tip of the medium 
suture smooth, with a more or less embrowned spot before 
the tip ; embolium yellow, with a fuscous spot at base ; the 
membrane tinged with brown ; the basal margin, nervures 
basally, and a broad, longitudinal streak running to the tip, 
blackish. Terguin with large clouded spots each side and 
behind ; connexivum bright yellow above, with a quadran- 
gular black spot at the base and apex of each segment, on 
the under side having a corresponding series of spots which 
are sometimes reduced to mere dots. Venter punctured 



400 THE GYPSY MOTH. 

with rufous and black, the latter arranged each side in a 
longitudinal series of patches ; interior to these is a row of 
black spots, and upon the middle line four round spots, with 
the largest one at the posterior end. 

"Length to tip of abdomen, 9 millims. Humeral width, 
5 millims. 

"No. 40, Harris Collection $ . ' Cambridge, Mass., April 
20, 1827.' 

' ' The specimens vary very much in depth of color and in 
the size and distinctness of the markings. 

"In my own collection are specimens from Maine and 
Minnesota. A female from Massachusetts is twelve millims. 
in length." 

In the imago state the antennae and tarsi (Plate 62, Figs. 
4 and 5) are increased by an additional joint, and become 
respectively five and three jointed. The imago varies in 
color from a blackish gray to a light brownish gray, though 
none of the specimens so far taken or reared are of as light 
color as P. modesties Dall. The males (Plate 62, Fig. 1), 
as a rule, are slightly smaller than the females (Plate Q2, 
Fig. 2), and their humeral angles are somewhat sharper, 
more nearly approaching those of P. spinosus Dall. 

For the identification of the specimens reared at the in- 
sectary I am indebted to the courtesy of Prof. P. R. Uhler. 

The following extract from notes upon an individual of 
the third brood, reared from eggs laid Aug. 14, 1895, will 
serve to illustrate the life history of a single generation : 
Predaceous bug, No. 142, Podisus serieventris Uhl. 

Hatched August 22 ; the first molt occurred August 26. 
Up to this date the bug had been fed upon the remains of 
four climbing cut- worms (JSToctua c-nigruni) . The second 
molt took place September 3 . Between the first and second 
molt it killed four larva? of JSToctua c-nigrum and two larva? 
of Rhynchagrotis cdternata. The bug molted for the third 
time September 8, having killed in the mean time two full- 
grown caterpillars of Vanessa antiopa and two of Anisota 
senatoria. The fourth molt occurred September 21. 
Between the third and fourth molt it had killed eio-ht full- 
grown caterpillars of Vanessa antiopa, two larva? of Ani- 



Explanation of Plate 62. 



Drawn by A. H. Kirkland. 



Podisus serieventris Uhl. 

i. Male imago. 4. Antenna of imago. 

2. Female imago. 5. Tarsus of imago. 

3. Rostrum of imago. 6. Wings of imago. 



PLATE 62. 




Kirkland 



SUFFOLK ENG. CO. 



PREDACEOUS HEMIPTERA. 401 

sola senator ia and one partly grown larva of Telea polyplte- 
mus. In the imago stage the insect (female) killed live 
larvae of Anisota senator ia. It was placed with a male Sep- 
tember 25, and mated September 30. On October 12, it 
was found partly hidden under some loose bark and leaves 
which had been placed in the bottom of the breeding-cage, 
and at the present writing (Jan. 1, 1896) it is still alive, and 
hibernating without having deposited its eggs. 

Feeding Habits. — In attacking a full-grown larva the 
bug apparently first makes a preliminary investigation, and, 
with antennae elevated, carefully inspects the caterpillar on 
all sides. After sidling around for some time, the point of 
attack is selected, usually the softer integument at the an- 
nulations of the body, the beak (Plate 62, Fig. 3) is swung 
down and out, projected horizontally forward and inserted 
in the side of the larva. Its entrance is at first unnoticed 
by the caterpillar, but after a few minutes a vigorous struggle 
ensues, which sometimes, but rarely, results in the bug being 
obliged to release its hold. In a short time the caterpillar 
grows weaker, apparently becomes stupefied, and the bug, 
after inserting its beak in new places, till the greater part 
of the body fluids have been extracted, finally leaves the 
dead, empty and flaccid larva hanging to the tree. The 
time consumed in feeding on a full-grown gypsy moth 
caterpillar varies from ten minutes to two or three hours, 
the bug as a rule feeding longest upon the thoracic seg- 
ments. 

The newly hatched bug seems to be unable to cope with 
large caterpillars, and I am led to believe that under natural 
conditions their early food is small larvae. On June 10, 
1895, at Winthrop, Mass., I found twelve nymphs of P. 
serieventris, of the first and second stage, feeding upon 
small, dark beetle larva?, which were abundant upon leaves 
of Plantago major. In the breeding cage the young nymphs 
were first fed upon the remains of soft-skinned larvae, such 
as RhyncJiagrotis alternata and JSfoctua c-nigrum, the cater- 
pillars being cut up into small bits before feeding them to the 
bugs. It was necessary to place the young bugs in close 
proximity to the food thus provided, and for this purpose a 



402 THE GYPSY MOTH. 

small camel's-hair brush was found to be of great assistance. 
After passing the first molt the nymphs were able to care 
for themselves, and would boldly attack full-grown cut- 
worms, of the species mentioned, when the latter were 
placed in the cages. With increasing age and size they fed 
readily upon hairy larvae (P. dispar, Tolype velleda, et ah). 
The period of greatest rapacity and of greatest growth is 
between the third and fourth molt, during which time the 
nymph feeds almost continuously. 

This insect has been taken in the field attacking all stages 
of the gypsy moth. Individuals in the first stage were this 
year found feeding upon the eggs of the gypsy moth, but 
when confined to this food died at the end of a few days. 
It is not an uncommon thing for them to attack a pupa, and 
on one occasion I found four nymphs in the second and third 
stages feeding upon a single female pupa. Female gypsy 
moths while depositing their egg-clusters, and males while 
mating, are also occasionally attacked by this insect. 

This species has been found feeding upon the larvae of 
Vanessa antiopa, Hyphantria cunea, Orgyia leucostigma, 
Attacus promethea, Clisiocampa americana and disstria and 
Paleacrita vernata. It has also been known to devour the 
dead imagoes of Limenitis Ursula and Pyrophila pyrami- 
doides. In confinement it readily attacks the larvae of 
Datana ministra, Attacus cecropia, Telea polyphemus, 
Anisota senatoria, Dryocampa rubicunda, Tolype velleda, 
Rhynchagrotis altemata, JSfoctua c-nigrum and Cimbex 
americana. 

When pressed by hunger these insects develop cannibal 
tendencies and feed upon other individuals of the same 
species, and also occasionally attack Podisus cynicus and 
Menecles insertus, while the two latter species have in turn 
been found feeding upon P. serieventris. I have seen P. 
serieventris feeding in confinement upon leaves of Quercus 
rubra, but I think it very doubtful if it is phyllophagous to 
any marked degree. 

Mating — Polygamy — Oviposition. — Mating takes place 
in from three to six days from the time the insect reaches 



PKEDACEOUS HEMIPTERA. 403 

the imago state. The time required for the process of 
mating varies from twelve to forty-eight hours. 

That the males of this species are polygamous is evident 
from the fact that one male confined in a breeding cage at 
the insectary successfully fertilized three females. With the 
exception of the females of the last brood, oviposition takes 
place in from eight hours to two or three days from the 
time of mating. The female deposits a cluster of from ten 
to thirty eggs, then rests and feeds for a few hours, but later 
resumes the work of egg-laying. In this way some three 
or four clusters of eggs are deposited, the whole process of 
egg-laying usually taking from one to four days. 

Hibernation. — That the insect hibernates in the imairo 
state seems to be an assured fact, since specimens of the 
last brood reared at the insectary, and left in the breeding 
cages out of doors, are alive at the time of this writing 
(Jan. 1, 1896). The imagoes of the last brood mate soon 
after reaching the mature form, and the fertilized females 
feed at intervals for a week or two ; but with the advent of 
cooler weather seek hibernating quarters, such as the crev- 
ices in the rough bark of trees, under burlap bands, etc., or 
even under the dead leaves upon the ground, sometimes 
burying themselves one or two inches beneath the surface. 
All of the males reared during the past year died without 
attempting to hibernate. 

Number of Annual Broods. During the summer of 1895, 
imagoes of this species were more or less abundant about the 
last of June and the middle of August, and in fewer numbers 
from the middle to the last of September, although individ- 
uals were taken throughout the summer. Nymphs were 
found in considerable numbers at such intervals, subsequent 
to the appearance of the imagoes, as would lead one to believe 
that they were distinct broods. I have reared two broods 
of this species between the last of June and the latter part 
of September; and this, in connection with the facts that 
young nymphs have been found in early June, and that the 
fertilized female imagoes of the last brood hibernate, would 
seem to be nearly conclusive evidence that the species is 
three-brooded in this region. 



404 THE GYPSY MOTH. 

Spiders. 

At occasional intervals during the past four years, spiders 
have been seen to attack and destroy the eggs, and also the 
caterpillars and imagoes, of P. dispar. In the summer of 
1895, a predaceous spider, found in Chelsea, was brought 
into the insectary and supplied with gypsy moth cater- 
pillars, which it readily destroyed. This spider was kindly 
determined by Mr. J. H. Emerton as Phidippus tripunctatus. 

Our common harvest spider (P/ haloing 'turn dorsatutn) was 
found by Mr. Mosher feeding on a male gypsy moth. 

Mites have been found so frequently destroying the eggs 
that we must acknowledge that in some localities they are 
very important factors in reducing the numbers of the gypsy 
moth. Mr. E. P. Felt observed the work of these mites on 
the gypsy moth eggs in confinement, and found that they 
destroyed the eggs very rapidly. They are most abundant 
in the fall, but do not feed to any marked degree during 
the winter. These mites were referred to Prof. Herbert 
Osborn, who determined them as two different species. The 
first was JSTothrus, near ovivorus Pack. (Plate 53, Fig. 14), 
and the other was Trombidium bulbipes Pack. (Plate 53, 
Fig. 15). A species of Phlozothrips (Plate 03, Fig. 13) was 
also found destroying the eggs. 

Insectivorous Vertebrates. 

Of the vertebrate enemies of the gypsy moth, the common 
skunk, Mephitis mephitica (Shaw), has been found feeding 
upon the female moths which were laying their eggs at the 
base of trees, or upon rocks, rubbish, etc. It is probable 
that these animals also feed upon the pupae to some extent 
in badly infested regions. 

The wood frog (Rana silvatica LeC.) has been reported 
in one instance as attacking the female moths. In August, 
1895, Mr. F. H. Mosher took a specimen of the tree frog 
(Hyla picker ingii Holbr.), feeding upon the caterpillars 
of the second brood of the gypsy moth, at Woburn. 

The common garden toad (Bufo lentiginosus arnericanus 
LeC.) was this year found by Mr. Kirkland to be devouring 



VEGETABLE PARASITES. 405 

great numbers of the caterpillars in infested brushlands. 
Stomach examinations of three toads, taken in such a place, 
June 6, 1895, showed them to contain respectively seven, 
fifteen and sixty-live gypsy moth caterpillars, or remains of 
the same. 

Mr. Samuel Henshaw published a report upon the gypsy 
moth in Massachusetts, in Bulletin No. 26, United States 
Department of Agriculture, Division of Entomology, page 
75, in which he gives the following list of invertebrates that 
destroy the larva? of the gypsy moth : Oicindela 6-guttata, 
Camponotus herculaneus, Sinea diadema, and undetermined 
Syrphus, and Chrysopa, Lithobius forficatus ; also the fol- 
lowing spiders : Epeira strix, Steatoda borealis, Lycosa sp., 
Drassus sp., Agalena ?icevia, Phidippus gdlathea (mysta- 
ceus), Epiblemum scenicum, Marptusa familiaris and 
Thomixus sp. 

Mr. Henshaw's letter of submittal is dated "Cambridge, 
Mass., Dec. 7, 1891," and therefore his observations were 
probably made during the summer of 1891. 

Vegetable Parasites. 

A very careful watch has been kept for any indication of 
vegetable parasites, either fungi or microbes, and nothing 
has thus far been discovered. We consulted with Drs. 
Farlow and Thaxter of Harvard University, both eminent 
authorities on the subject, and, after describing to them the 
habits of the insect, neither of these gentlemen gave us en- 
couragement that vegetable parasites would prove to be a 
very important factor in the destruction of the gypsy moth ; 
yet, in wet seasons, where the caterpillars were very abun- 
dant, the parasitic fungi, if any could be found to attack this 
species, might prove more or less serviceable. 

The caterpillars of the nun moth (Lymantria monacha), 
in Europe, when very abundant, are often attacked by an 
epidemic or contagious disease known as the top or head 
sickness (Wipfelkrankheit), a very good account of which 
has been given by vVachtl and Kornauth in their " Beitrage 
zur Kenntniss der Morphologie, etc., der Xonne," page 17. 
Drs. Tangl, Scheuerlen, Hofmann, Tubeuf and Jager have 



406 THE GYPSY MOTH. 

made careful investigations of this disease, but have had 
very little success in inoculating healthy caterpillars with 
cultures made from those which were diseased. 

Importing Parasites. 
No attempt has been made to import parasites thus far, 
for the reason that the law requires the work to be con- 
ducted with direct reference to the extermination of the 
gypsy moth, and, therefore, the general destruction of the 
insect would also destroy the parasites. There is no reason 
why our native Hymenopterous parasites may not prove 
quite as effective as those of any other country, since there 
is no parasite known which confines itself exclusively to the 
gypsy moth, and, as has been shown, we have several species 
which attack it as readily as any in its native country. 

Insect ary. 

In the early part of the work on the gypsy moth, the 
more difficult and important experiments and observations 
were conducted in the insectary at Amherst ; but it seemed 
desirable, and even necessary, to repeat many of the ex- 
periments on a far more extensive scale than was possible 
at that place, and it was therefore decided to fit up and equip 
a room for this purpose, in the store-house on Commercial 
Street, Maiden. This building stands on piles, about six 
feet from the ground, which is swampy and wet. The front 
of the building is on a level with the street, which is built 
up to the grade indicated. 

In the room thus fitted up many experiments were con- 
ducted, a large number of which gave very satisfactory 
results. But in the experiments on insecticides, where a 
check series was conducted, with no poisons used on the 
food, the mortality was often so great that we felt very un- 
certain about the results in the cages where the caterpillars 
were fed on leaves sprayed with insecticides, whether they 
died from the effects of the poison, or because of the un- 
healthful surroundings. 

In the early part of the summer of 1895, a small lot of 
land, in the edge of the woodland in the suburbs of Maiden, 




PLATE 63. Experiment station and insectary, Maiden, Mass. 



INSECTICIDES. 407 

was leased, and an insectaiy was erected for experimental 
purposes. This building (Plate 63) is sixteen by twenty 
feet on the ground, with a greenhouse on the south side, six 
by eight feet, and a covered shed on the north side, seven 
by eight feet. It contains, on the first floor, besides the 
main laboratory with tables, closets, etc., a private labora- 
tory and a chemical room. The second floor contains a 
lodging-room for the employees. 

The experimental work carried on in this building, during 
the summer of 1895, has proved far more satisfactory than 
that in the building on Commercial Street, because of the 
greater conveniences and more healthful conditions. 

Insecticides. 
Experiments with Substances for destroying Eggs. 

The value of egg-destruction, as an exterminative meas- 
ure, was recognized at an early stage in the work of com- 
bating the gypsy moth, and led to an extensive study of 
substances which might be advantageously used for this 
purpose. The requisites necessary in such a substance arc : 
that it shall be effective wherever applied ; that it shall 
leave a permanent stain or color, enabling one to distinguish 
treated from untreated egg-masses ; and that its price shall 
be within practical limits. The substances found to be 
of the greatest value, together with an explanation of the 
method of applying them, have already been described in 
Part I. 

During the year 1892, Mr. F. C. Moulton experimented 
with the following substances on the eggs of the gypsy 
moths, to discover something that could be readily applied 
to the egg-clusters and effectually destroy them. To some 
of the preparations were added substances which contain no 
destructive power, but were used simply to change the color 
of the egg-clusters on trees, so that those which had been 
treated might be readily distinguished from the others. 

Ammonia. — January 21. Five egg-clusters were treated 
for five minutes with ammonia gas, made by heating strong 
aqua-ammonia. Apparently the eggs were not affected, for, 
by March 24, nearly all had hatched. 



408 THE GYPSY MOTH. 

Benzine. — January 22. A small amount of benzine was 
poured upon an egg-cluster and then allowed to evaporate. 
Apparently the eggs were not affected, for by March 24, 
about three-tenths of them had hatched. Neatly five-tenths 
of the caterpillars died while hatching. 

Bromine. — January 19. Five egg-clusters were placed 
in a box and a small amount of liquid bromine turned on 
them. At the end of fifteen minutes they were entirely 
destroyed. 

Bromine Vapor. — January 19. Five egg-clusters were 
submitted to the action of bromine vapor in a closed box 
for ten minutes. At the end of this time the eggs were 
destroyed. Another experiment on the same date, in which 
the eggs were exposed for fifteen minutes, gave similar re- 
sults. From egg-clusters treated, on the same date, with 
bromine vapors for a period of ten minutes, the vapor not 
being closely confined, a few caterpillars hatched. Four 
caterpillars hatched from other egg-masses treated in the 
same manner. 

Chlorine. — January 15. One egg-cluster was submitted 
for five minutes to the action of chlorine gas, made by add- 
ing ten parts (by weight) of hydrochloric acid to eight 
parts of black oxide of manganese, and then applying a 
strong heat to the mixture. The egg-cluster was bleached 
and the eggs destroyed. Four other experiments, in which 
egg-clusters were exposed to the action of chlorine for 
seven, ten, fifteen and thirty minutes respectively, gave 
similar results. March 12. Some chloride of lime was put 
into a flask and sulphuric acid added to it. The chlorine 
was then conducted into a bottle containing gypsy moth 
egg-clusters. It entirely destroyed the eggs, with but one 
exception. January 19. Five egg-clusters were treated 
with chlorine under a hood made of oil-cloth stretched over 
a frame, but, as the oil-cloth was not large enough to en- 
tirely cover it, a part of the gas escaped. One egg-cluster 
was bleached, while the others were apparently not affected ; 
about one-third of the eggs hatched the following spring. 

Carbon Bisulphide. — January 19. Five egg-clusters 
were submitted to the action of hot vapors of carbon bi-sul- 



INSECTICIDES. 409 

phide for five minutes. The carbon bi-sulphide was put 
into a flask and slightly heated, the vapors passing over a 
bottle containing the egg-clusters, condensing and wetting 
them, which caused the eggs to become white and soft, after 
which they all dried up. Two lots of eggs exposed to the 
vapors of carbon bi-sulphide, in a similar manner, for ten 
and fifteen minutes respectively, were completely destroyed. 
January 19. Five egg-clusters, placed in a tin box covered 
with paper, were treated for fifteen minutes with carbon bi- 
sulphide, which caused them to grow white and soft, thus 
destroying them. January 21. Five egg-clusters were 
treated with cold vapors of carbon bi-sulphide for fifteen 
minutes, care being taken that the vapors should not wet 
the egg-clusters. The eggs apparently were not affected, 
and, by the 24th of March, about one-half of them had 
hatched. January 25. Five egg-clusters were treated for 
fifteen minutes to the action of cold vapors of carbon bi-sul- 
phide. The eggs were placed in a glass, which was put in 
a large tin box containing carbon bi-sulphide. The eggs 
were not affected by this treatment, and, by the 24th of 
March, all had hatched. February 9. A number of egg- 
clusters were treated in the same manner as in the preced- 
ing experiment, and, although the eggs did not appear to 
be affected, none hatched. 

Calcic Chloride. — January 21. One egg-cluster was 
soaked for half a day in a solution of calcic chloride, made 
by dissolving one-eighth ounce of calcic chloride in two 
cubic centimeters of water. The solution did not penetrate 
the egg-cluster, and nearly all the eggs hatched. 

Corrosive Sublimate. — February 1 . A few crystals of 
corrosive sublimate were dissolved in alcohol, and the solu- 
tion poured over five egg-clusters. March 22, some of the 
eggs had partly hatched, but the caterpillars soon died. 
February 1. Five egg-clusters were treated in the same 
manner as in the preceding experiment. Two or three 
caterpillars hatched and others came partly out of the shell, 
but, March 22, all were dead. Three other lots of eggs were 
treated in the same manner, March 3. None of these eggs 
hatched. 



410 THE GYPSY MOTH. 

Creosote Oil. — March 14. A small amount of creosote 
oil was dropped upon live egg-clusters, and, although it did 
not appear to injure the eggs, none of them hatched. March 
31. A mixture of creosote oil and pine tar, fifty per cent, 
of each, was dropped upon some egg-clusters. It pene- 
trated them at once, and, later, shrivelled the eggs so that 
none hatched. March 31. Another lot of eo-<r-clusters was 
treated in the same manner, and the eggs destroyed. Two 
experiments with a mixture of creosote oil, fifty per cent., 
and turpentine, fifty per cent. , gave results like those of the 
preceding experiments. April 7. About eight thousand 
eggs were saturated with a solution of pine creosote oil, 
forty-live per cent., turpentine, forty-five per cent., and 
coal tar, ten per cent. It penetrated the egg-clusters read- 
ily, and attacked the eggs so that none hatched. 

Coal Tar. — March 5. A mixture of coal tar, thirty per 
cent. , phenol, forty per cent. , and turpentine, thirty per cent. , 
was dropped upon ten egg-clusters. It quickly penetrated 
the eggs, turning them black and softening the shell so that 
none hatched. Several other experiments with similar tar 
mixtures gave equally as satisfactory results. 

Eagle Mills Pou-der . — March 11. A mixture of Eagle 
Mills Powder, fifty per cent., and turpentine, fifty per cent., 
was dropped upon ten egg-clusters, but the mixture was too 
thick to penetrate. March 11. A solution of Eagle Mills 
Powder, ten per cent., water, sixty per cent., and alcohol, 
thirty per cent., was dropped on some egg-clusters, and 
quickly penetrated to the bottom. This did not injure the 
eggs, for, by April 12, nearly all had hatched. 

Hydrocyanic Acid Gas. — January 11. One egg-cluster 
was submitted to the action of pure concentrated hydro- 
cyanic gas, in the following apparatus : A Florence flask, 
containing one-half an ounce of potassium cyanide and about 
twenty cubic centimeters of water, was connected with a 
wide-mouthed bottle by a tube bent twice at right angles. 
The bottle also contained an escape tube. An unbroken 
egg-cluster was placed in the bottle, then sulphuric acid was 
added to the potassium cyanide in the flask. The hydro- 
cyanic acid gas passed over into the bottle, driving the air 



INSECTICIDES. 411 

out through the delivery tube. After the air was all out, 
the delivery tube was stopped by a cork ; and, as the action 
was still going on, the gas in the apparatus was under pres- 
sure and remained so for thirty minutes, when the egg- 
cluster was removed. No change could be detected, either 
with the naked eye or by use of the microscope, and, by 
March 24, about one-half of the eggs had hatched. On the 
same date, nine other egg-clusters were treated in the same 
manner, using the same apparatus under the same condi- 
tions. An examination of the eggs failed to show any 
change. These eggs hatched February 6. January 12. 
Five egg-clusters were treated with hydrocyanic acid gas, 
for thirty minutes, under a hood made by spreading oil- 
cloth over three bottles. The edge of the cloth came down 
to the table, but not close enough to exclude the air, as there 
were numerous crevices under the cloth. The density of 
hydrocyanic acid gas, being .706, causes it to rise. The 
egg-clusters were placed on a small card-board stand which 
reached nearly to the top of the hood, which was punctured 
several times, so that the gas might readily pass through. 
Forty cubic centimeters of sulphuric acid were then added 
to one-half ounce of potassic cyanide, the gas being passed 
under the hood. No change was visible in the es-o-s after 
this treatment, and nearly all of them hatched. January 12. 
Five egg-clusters were treated with hydrocyanic acid gas, 
under a hood made of wet unbleached cotton, the cloth beins; 
drawn closely to the table and weighted down, so that no air 
could pass under the hood; with this exception, the process 
and conditions were the same as in the preceding experi- 
ment. Nearly all of the eggs hatched after being subjected 
to this treatment. January 12. Ten egg-clusters were 
treated with pure, concentrated hydrocyanic acid gas for 
one hour. The apparatus consisted of three four-ounce 
Florence flasks, marked A, B and C. Flask A contained 
about one-half an ounce of potassic cyanide, B contained 
concentrated sulphuric acid, and C the ten egg-clusters. A 
was connected with B by means of a tube which dipped 
below the surface of the sulphuric acid in B. The escape 
tube from B passed through the stopper of C. There was 



412 THE GYPSY MOTH. 

also a small escape tube for the air to pass out. Sulphuric 
acid was added to the potassic cyanide in flask A, and the 
hydrocyanic acid gas passed through the sulphuric acid in 
B, which thoroughly dried it ; it then passed out into C. 
After the air had all passed out of C, the escape tube was 
stopped. The gas was generated for an hour, after which 
time an examination of the eggs showed no change, and 
nearly all of them subsequently hatched. A duplicate ex- 
periment gave similar results. January 13. Five egg- 
clusters were treated with pure, concentrated hydrocyanic 
acid gas for one hour and a half. None of the eggs hatched. 
January 13. Five egg-clusters were treated for two hours 
with hydrocyanic acid gas under a hood. An examination 
of the eggs, made January 11, showed them to be slightly 
dried, but, by March 24, about eight-tenths of the eggs had 
hatched. January 15. Five egg-clusters were treated with 
hydrocyanic acid gas for fifteen minutes. The eggs did not 
appear to be affected, although none of them hatched. 

Hydrogen Arsenide. — April 7. Five egg-clusters were 
treated for fifteen minutes with hydrogen arsenide, made by 
pouring a solution of arsenic into a mixture of granulated 
zinc and hydrochloric acid. None of these eggs hatched. 
November 5. A number of egg-clusters were treated for 
one hour with hydrogen arsenide. None of the eggs 
hatched. February 6. About twenty-five broken egg-clus- 
ters were treated with hydrogen arsenide for forty-five 
minutes. The gas was made as follows : A solution of 
arsenic was poured into a mixture of hydrochloric acid and 
zinc. The gas which was given off was dried by passing 
through a U tube containing calcium chloride, then into the 
bottle containing the eggs. None hatched. Several other 
experiments with this gas gave similar results. 

Hydrogen Sulphide. — April 7. Some egg-clusters were 
submitted to the action of hydrogen sulphide for ten 
minutes. At the end of this time the eggs were shrivelled 
and none hatched. January 30. Several egg-clusters were 
treated for one hour with hydrogen sulphide gas, which was 
made by adding dilute sulphuric acid to iron sulphide. It 
was passed through a U tube and then into a bottle con- 




PLATE 64. Pine and other trees attacked by the gypsy moth 
caterpillars at Lexington. 



INSECTICIDES. 413 

taming the egg-clusters. None hatched. Februarys. Ten 
egg-clusters were treated with hydrogen sulphide for one 
hour. None hatched. April 12. Some broken egg-clus- 
ters were treated, in an open bottle, for two hours, with 
hydrogen sulphide. None of them hatched. 

Hydrochloric Acid Gas. — March 31. Some egg-clusters 
were submitted for fifteen minutes to the action of hydro- 
chloric acid gas, formed by adding sulphuric acid to salt. 
This destroyed the eggs by drying them up. Several egg- 
clusters were submitted to the action of hydrochloric acid 
gas for thirty minutes. None hatched. 

" Infernal" Mixture. — February 17. A number of new 
egg-clusters were treated with a gas made by adding fifty 
per cent, of sulphuric acid to fifty per cent of turpentine. 
They were left exposed to the action of the gas over night, 
which destroyed them so that none hatched. February 19. 
Five egg-clusters were treated for two hours with this gas. 
The ej^s were bleached a little, and none hatched. Febru- 

OO 

ary 22. Five egg-clusters were subjected for five hours to 
the action of the above-mentioned gas. The eggs were 
stained red, and shrivelled so that none hatched. February 
22. Five egg-clusters were submitted for ten hours to the 
action of this gas, which entirely destroyed the eggs. Eggs 
exposed to the action of this gas on February 19, for a 
period of thirty minutes, were uninjured, and hatched on 
March 24. 

Nitrogen Dioxide. — March 31. Several egg-clusters 
were submitted to nitrogen dioxide for fifteen minutes. The 
gas was formed by adding sulphuric acid to salt and nitre. 
The eggs were entirely destroyed. April 1. A number of 
eo-o-_clusters were submitted for five minutes to the action 

OO 

of nitrogen dioxide. The eggs were entirely destroyed. 
August 24. Eggs were treated with nitrous dioxide in a 
hollow tree. The gas was generated as in the preceding 
experiments. After this treatment the eggs were taken into 
a warm room, where they began to hatch on February 31. 

Potassic Cyanide. — March 15. A solution of potassic 
cyanide in water, fifty per cent., and of alcohol, fifty per 
cent., was dropped upon five egg-clusters, which it pene- 



414 THE GYPSY MOTH. 

trated readily, but did not affect the vitality of the eggs. 
March 15. Several egg-clusters were treated in the same 
manner as in the preceding experiment, and about one-tenth 
of the eggs hatched. 

Pine Tar Mixtures. — February 1. A mixture, com- 
posed of fifty per cent, of pine tar and fifty per cent, of 
phenol, was poured upon five egg-clusters. It soaked into 
the clusters readily, and blackened them, apparently de- 
stroying the eggs. February 3. A mixture of pine tar, 
fifty per cent., and turpentine, fifty per cent., was dropped 
upon five egg-clusters. It penetrated readily, turning the 
eggs black and apparently destroying them. February 3. 
A mixture containing equal parts of pine tar, phenol and 
turpentine was dropped upon five egg-clusters, completely 
destroying the eggs. A mixture composed of forty per 
cent, of pine tar, forty per cent, of phenol, twenty per cent, 
of alcohol, with corrosive sublimate, was dropped upon ten 
egg-clusters, and, although the eggs did not appear to be 
destroyed, none hatched. March 6. A mixture of pine 
tar, fifty per cent., alcohol, forty-five per cent., tannic acid, 
two and one-half per cent., and ferrous sulphate, two and 
one-half per cent., was dropped upon a number of egg- 
clusters, which it readily penetrated, rendering the eggs soft. 
The object of the last two substances was to give the solu- 
tion a black color. March 6. A mixture of pine tar, fifty 
per cent., alcohol, forty-five per cent., and Stafford's ink, 
five per cent., was dropped upon some egg-clusters. It 
readily penetrated to the bottom layer, destroying the 
eggs. 

Phenol. — January 21. A small amount of liquid phenol 
was poured upon an egg-cluster. This burned the eggs to 
a crisp. January 21. Five egg-clusters were treated for 
ten minutes with vapors of phenol, one hundred per cent., 
care being taken that the egg-clusters should be dampened 
by the vapors. The eggs were badly burned. January 21. 
Five egg-clusters were treated for fifteen minutes in the 
same manner as in the preceding experiment, except that 
the vapors were not allowed to w r et the egg-clusters. Ap- 
parently the eggs were not injured, for, by March 24, nearly 



INSECTICIDES. 415 

all had hatched. January 25. A mixture of phenol, ten 
per cent., and alcohol, ninety per cent., was poured upon 
live egg-clusters, which were blackened and burned. Jan- 
uary 25. Five egg-clusters were treated with a mixture of 
phenol, twenty per cent., and water, eighty per cent. This 
mixture was stirred until it became milky white, then a little 
was poured upon the egg-clusters, and seriously burned 
them. January 30. A mixture of phenol, four per cent., 
and water, ninety-six per cent. , was poured upon live egg- 
clusters. The mixture penetrated only a part of the egg- 
cluster, and nearly one-half of the eggs hatched. January 
30. A mixture of phenol, three per cent., and water, 
ninety-seven per cent., was poured upon live egg-clusters. 
About nine-tenths of the eggs hatched. February 1. A 
mixture composed of phenol, fifty per cent., and sulphuric 
acid, fifty per cent., was dropped upon five egg-clusters. 
This mixture slowly penetrated the egg-clusters and de- 
stroyed the eggs. February 2. A mixture containing fifty 
per cent, alcohol, twenty-five per cent, phenol and twenty- 
five per cent, of sulphuric acid, was dropped upon five egg- 
clusters, destroying the eggs. February 26. A mixture 
of fifty per cent, alcohol, twenty-five per cent, phenol, 
twenty-five per cent, sulphuric acid, with a little potassic 
ferricyanide and ferrous chloride, was dropped upon some 
egg-clusters. The mixture readily penetrated the clusters, 
turning them dark blue and completely destroying the eggs. 
February 2. A mixture of alcohol, fifty per cent., phenol, 
twenty-five per cent., and sulphuric acid, twenty-five per 
cent., was dropped upon five egg-clusters. It readily pene- 
trated the clusters, turning them black and completely de- 
stroying the eggs. February 25. A mixture of alcohol, 
sixty per cent., phenol, twenty per cent., and sulphuric 
acid, twenty per cent., was dropped upon some egg-clusters, 
turning them black and completely destroying the eggs. 
March 1. A mixture of phenol, fifty per cent., turpentine 
and nitric acid, fifty per cent., was dropped upon some 
egg-clusters, entirely destroying the eggs. March 14. A 
mixture composed of phenol, fifty per cent., turpentine with 
a small amount of concentrated nitric acid, fifty per cent., 



416 THE GYPSY MOTH. 

was dropped upon some egg-clusters, entirely destroying 
the eggs. 

Pyroligenous Acid. — February 10. Eight egg-clusters 
were moistened with pyroligenous acid, but it would not 
penetrate the clusters. 

Spruce Gum. — Twenty per cent, of spruce gum, thirty- 
five per cent, of rosin, thirty-five per cent, of cotton-seed 
oil, five per cent, of turpentine and five per cent, of pine 
tar were melted and mixed together, and some egg-clusters 
saturated with the solution. None of the eggs hatched. 

Sulphur Di-oxide. — January 25. Five egg-clusters 
were placed in a tight box and submitted for ten minutes to 
the fumes of burning sulphur. March 24, about three-fifths 
of the eggs had hatched. January 25. Five egg-clusters, 
placed in a tight wooden box, were submitted for twenty 
minutes to the fumes of burning sulphur. March 24, nearly 
all of the eggs had hatched. 

Turpentine. — A quantity of turpentine was poured on 
five egg-clusters. It readily penetrated, but apparently did 
not affect the eggs, as nearly all of them hatched. 

During the month of October, 1893, Mr. C. W. Minott 
experimented in the field with a number of mixtures having 
creosote oil as a basis. All of these mixtures were effective 
in destroying the eggs of the gypsy moth. The lowest per 
cent, of creosote oil used was in a mixture composed of 
eighty per cent, of turpentine and twenty per cent, of creo- 
sote oil. Even when diluted to this degree, it was found to 
be effective. 

The following experiments on the eggs of the gypsy moth 
were conducted by Mr. Kirkland, in 1895 : — 

Kerosene. — January 5. Twelve egg-clusters were treated 
with kerosene oil ; these hatched April 20. April 25. Five 
egg-clusters treated with kerosene oil ; hatched May 1 . 

Turpentine. — January 5. Ten egg-clusters treated with 
turpentine; hatched April 18. 

Kerosene and Turpentine. — May 2. Egg-clusters which 
had commenced hatching were soaked in a mixture com- 
posed of equal parts of kerosene and turpentine. May 6. 



INSECTICIDES. 417 

Six eggs-clusters r,e-cormnenced hatching, and a few cater- 
pillars emerged. 

Crude Castor Oil and Turpentine. — January 5. Five 
egg-clusters, treated with the above mixture, hatched April 
30. 

Para fine Gas or Residuum Oil. — Thinking this oil might 
be of some value for treating egg-clusters, a number of 
experiments were made which gave very satisfactory re- 
sults. January 5. Twelve egg-clusters were treated with 
paraffine gas oil, none of which hatched. During the winter 
and spring of 1895, from one hundred to two hundred egg- 
clusters were treated with paraffine gas oil, with the result 
that none of them hatched. 

Raupenleim. — April 27. Five egg-clusters were care- 
fully covered with Raupenleim, the layer being about one- 
eighth of an inch thick. None of the eggs hatched. 

The experiments in treating egg-clusters with various 
gases were made with a view to finding some practical way 
of dealing with stone walls, hollow trees and other more or 
less inaccessible places, in which eggs had been laid in 
large quantities. The substances which were found to give 
the most satisfactory results, i. e., chlorine and bromine 
vapors, were tested on a large scale in the field, but here 
their use was found to be, at best, only partially effective. 

Insecticides for Destroying the Caterpillars. 
Spraying with the common arsenical poisons, such as 
Paris green, London purple, etc., was one of the first 
methods employed for the destruction of the caterpillars 
of the gypsy moth, and the failure of these poisons to do 
effective work in the field has already been stated. When 
it became evident that the caterpillars were not being de- 
stroyed in any great numbers by these poisons, an effort 
was made to discover a more effective poison, and much 
time and labor were spent in this undertaking. The most 
careful attention was given to this problem ; for, with 
modern spraying machinery, the thorough application of 
a poison to trees is easily accomplished, and thus a cheap, 



418 THE GYPSY- MOTH. 

practical and effective method of destroying the caterpillars 
of the gypsy moth would be provided if a poison could be 
found which would meet the exigencies of the case. It will 
be seen by the records which follow that we have experi- 
mented with insecticides in general use, which are adapted 
to our work, and also with many new insecticides which 
were prepared for this purpose by our former chemist, 
Mr. F. C. Moulton. 

All of the insecticide experiments here recorded were 
performed under my immediate supervision, by Messrs. 
Reid and Schrader in 1893, Messrs. Minott, Mosher and 
Kirkland in 1894, and by Mr. Kirkland and his assistants 
in 1895. 

Details of the Experiments. 

The caterpillars used in the field or out-door experiments 
were taken from infested trees near the place of experi- 
mentation. Those used in the in-door experiments were, 
as a rule, from eggs hatched early in the season by means 
of artificial heat. 

In the in-door experiments on young caterpillars lettuce 
was the food plant generally used, leaves of elm, apple or 
willow being substituted as soon as such foliage could be 
obtained. In the field experiments the caterpillars were 
confined upon branches of trees on which they were known 
to feed readily. 

All poisons used in the experiments of 1893, and the 
greater part of those used in 1894, were carefully weighed 
out in the insectary at Amherst. During the latter part 
of 1894, and throughout the season of 1895, they were 
weighed on a very accurate set of balances at the Maiden 
office. 

The poison was applied to the foliage used in the in-door 
experiments both by dipping the leaves in the poison mixt- 
ures and by spraying with small hand bellows. In the 
field experiments the poison was always applied by use of 
the spraying bellows. After heavy rains the branches on 
which the caterpillars were confined were resprayed in the 
same manner as would be adopted in spraying operations 
in the field. In nearly all cases a small amount of glucose 



INSECTICIDES. 419 

was added to the poison mixtures, in order to increase the 
adhesive qualities. In the experiments conducted at the 
insectary the caterpillars were confined in glass jars or in 
lantern globes. In the field experiments the caterpillars 
were sacked in (enclosed by means of a thin cloth bag of 
proper dimensions) upon the branches of trees. In the case 
of the in-door experiments the poisoned food was renewed 
and the jars cleaned daily. For the field experiments 
branches of sufficient size to allow the caterpillars to feed 
till reaching maturity were chosen, and thus, as a rule, no 
change was necessary. 

Each jar or sack used in the experiments was given a 
number, which was recorded in a book, in which the records 
of the ten caterpillars used in each experiment were carefully 
noted. In many of the experiments a ' ' check " was em- 
ployed, to determine the normal death rate of caterpillars 
feeding on unpoisoned food. This check consisted of the 
same number of caterpillars confined in a jar or bag in the 
same manner as those in the experiment, with the exception 
that they were kept supplied with fresh, unpoisoned food. 

Daily observations were made both upon caterpillars feed- 
ing on the poisoned and unpoisoned food, and the results 
recorded. Many of the experiments on young caterpillars 
were discontinued at the end of about a fortnight, or after 
they had entered the succeeding molt. 

The following pages contain the records of the experi- 
ments which have been conducted with the different insecti- 
cides : — 

Experiments with Paris Green. 
h lb. Paris Oreen to 150 gal. Water. 

No. 1. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of \ lb. to 150 gal. of 
water. Two died on the third, three the fourth, one the 
fifth, three the sixth and one the seventh day. 

Check experiment : none dead. 

No. 2. — April 26, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of £ lb. to 150 gal. of water. 



420 THE GYPSY MOTH. 

Three died the second, three the third, one the fourth and 
one the fifth day, and two escaped. 

Check experiment : none dead. 

No. 3.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of £ lb. to 150 gal. of 
water. Two died the third, one the fourth, three the sixth, 
two the seventh and two the eighth day. 

Check experiment : one died the third day. 

No. 4. — June 10, 1894. Ten caterpillars of the second 
molt were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of £ lb. to 150 gal. of 
water. One died on the seventh, two the eighth, five the 
ninth and two the tenth day. 

Check experiment : none dead. 

No. 5. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of \ lb. to 150 gal. of 
water. One died the fourth, two the fifth, two the sixth, 
two the seventh, one the eighth, one the ninth and one the 
eleventh day. 

Check experiment : none dead. 

No. 6. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of £ lb. to 150 gal. of 
water. Three died the third, two the fourth, one the fifth, 
one the sixth and three the seventh day. 

Check experiment : one died the fifth and one the sixth 
day. 

No. 7 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of £ lb. to 150 gal. of water, and ten fourth-molt 
caterpillars placed upon it. July 5, the foliage was so badly 
burned that the caterpillars were removed to an unsprayed 
branch. July 30, the food supply having given out, they 
were again removed to another unsprayed branch. Five 
of these caterpillars died before pupating, and, of the five 
that began to pupate, three emerged. Foliage very badly 
burned. 



INSECTICIDES. 421 

No. 8 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of £ lb. to 150 gal. of water, and six fourth-molt 
caterpillars placed upon it. July 5, the foliage was so badly 
burned that the caterpillars were transferred to a freshly 
sprayed oak branch. July 19, the branch was resprayed 
on account of heavy rains. Of the six caterpillars, only 
two, and possibly one of these was injured, died before 
pupating. Of the four that pupated, two emerged. The 
foliage of the hop-hornbeam was very badly burned, while 
that of the oak was in good condition. 

No. 9.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of £ lb. to 150 gal. of 
water. One died the third day ; one pupated the fourth, 
three the seventh and three the eighth day ; two died the 
eleventh day. 

Check experiment : three pupated the fourth day ; one 
died the seventh and one the eighth day. 

No. 10 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of £ lb. to 150 gal. of water. One died the eighth and one 
the eleventh day ; one pupated the thirteenth day ; one died 
and two pupated the fourteenth day ; one pupated the twen- 
tieth, one the twenty-third, one the twenty-eighth and one 
the twenty-ninth day. 

No. 11 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of £ lb. to 150 gal. of water, and ten caterpillars, of 
the fifth molt, placed upon it. July 5, the foliage was so 
badly burned that the caterpillars were transferred to a 
freshly sprayed branch of oak. On the 15th of July, for 
lack of food, they were again removed to another branch of 
oak which had also been sprayed. Only one caterpillar 
died before pupating, and that one lived twenty-four days 
after the first spraying. Of the nine that pupated, five 
emerged. The foliage of the hop-hornbeam was very badly 
burned, while that of the oak was only slightly so, if at all. 



422 THE GYPSY MOTH. 

No. 12 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of £ lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 5 , the foliage was so badly 
burned that the caterpillars were removed to another branch 
of hop-hornbeam which was not sprayed. July 11, the 
foliage having been entirely stripped from the branch, they 
were again removed to another unsprayed branch. Of these 
caterpillars, none died before pupating, and four of them 
completed the process of pupation and emerged. Foliage 
very badly burned. 

f lb. Paris Green to 150 gal. Water. 

No. 13. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of ^ lb. to 150 gal. of 
water. Four died the second, five the third and one the 
fourth day. 

Check experiment : none dead. 

No. 14. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of | lb. to 150 gal. of water. 
Three died the second, four the third, two the fifth and one 
the sixth day. 

Check experiment : none dead. 

No. 15.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of ^ lb. to 150 gal. of 
water. One died the fourth, one the fifth, one the sixth, 
one the seventh, three the eighth and three the ninth day. 

Check experiment : none dead. 

No. 16. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of | 11). to 150 gal. of 
water. One died the fifth, one the seventh, three the eighth, 
two the ninth and three the eleventh day. 

Check experiment : none dead. 

No. 17. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 



INSECTICIDES. 423 

with Paris green, in the proportion of | lb. to 150 gal. of 
water. One died the second, three the third, three the fifth, 
three the sixth and one the seventh day. 

Check experiment : one accidentally killed the seventh 
day. 

No. 18. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of | lb. to 150 gal. of 
water. Two died the second, three the third, three the fifth 
and two the sixth day. 

Check experiment : one pupated the third and one died 
the fourth day. 

No. 19 (field experiment). — June 27, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of ^ lb. to 150 gal. of water, and six fourth-molt 
caterpillars placed upon it. July 8, the foliage was so 
badly burned that the leaves fell off, and the caterpillars 
were removed to another branch which had not been sprayed. 
By August 12, all of the caterpillars were dead, with the 
exception of one which pupated and emerged. 

No. 20 (field experiment) .— June 27, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of ^ lb. to 150 gal. of water, and ten fourth-molt 
caterpillars were placed upon it. July 8, one caterpillar 
had died and the foliage had become badly burned. The 
remaining caterpillars were transferred to a freshly sprayed 
oak branch. July 19, all the caterpillars were dead. Foli- 
age slightly burned. 

No. 21.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of ^ lb. to 150 gal. of 
water. One died the second and one the third day ; two 
died and one pupated the fourth day ; two died and one 
pupated the sixth day ; one died the eleventh and one the 
twelfth day. 

Check experiment : one pupated the third day ; one died 
the fourth day ; one pupated the sixth, two the eighth, one 
the ninth and one the eleventh day. 

No. 22 (field experiment). — July 7, 1894. Ten cater- 



424 THE GYPSY MOTH. 

pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of | lb. to 150 gal. of water. Two died and one pupated 
the seventh day ; two pupated the fourteenth, two the six- 
teenth, one the nineteenth, one the twenty-first and one the 
twenty-third day. 

No. 23 (field experiment). — June 27, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of 4 lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 8, one died, and the food 
having given out, those remaining were transferred to an- 
other branch. Of these, six pupated and emerged, while 
the other three pupated, but died without emerging. The 
foliage which was sprayed was so badly burned that the 
leaves curled and fell oft*. 

No. 24 (field experiment). — June 27, 1894. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of £■ lb. to 150 gal. of water, and nine fifth-molt 
caterpillars placed upon it. July 8, two having died, the 
remaining caterpillars were transferred to a freshly sprayed 
oak branch, as the foliage of the hop-hornbeam was burned 
to a crisp. By the 4th of August all the caterpillars were 
dead. While the foliage of the hop-hornbeam was badly 
burned, that of the oak remained in good condition. 

1 lb. Paris Green to 150 gal. Water. 

No. 26. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 1 lb. to 150 gal. of 
water. Two died the first, five the third and one the fourth 
day ; two escaped. 

Check experiment : none dead. 

No. 27. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of 1 lb. to 150 gal. of water. 
One died the first, two the second, five the third, one the 
fourth and one the fifth day. 

Check experiment : none dead. 

No. 28. -^May 28, 1894. Ten caterpillars, of the first 



INSECTICIDES. 425 

molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 1 11). to 150 gal. of 
water. Three died the third, one the fourth, one the fifth, 
four the sixth and one the seventh day. 

Check experiment : one dead. 

No. 29. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1 lb. to 150 gal. of 
water. One died the second, one the third, two the fourth, 
one the fifth, four the seventh and one the eighth day. 

Check experiment : none dead. 

No. 30. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1 lb. to 150 gal. of 
water. Two died the second, three the third, two the 
fourth, one the sixth and two the seventh day. 

Check experiment : none dead. 

No. 31.— June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1 lb. to 150 gal. of 
water. Four died the third, one the fourth, one the fifth, 
two the sixth, one the seventh and one the eighth day. 

Check experiment : one died the fifth day ; one pupated 
and one died the sixth day. 

No. 32 (field experiment). — June 26, 1893. A branch 
of apple tree was sprayed with Paris green, in the propor- 
tion of 1 lb. to 150 gal. of water, and ten fourth-molt cater- 
pillars placed upon it. Of these, four died without pupating, 
and, of the six which began to pupate, none emerged. 
Foliage slightly burned. 

No. 33 (field experiment) . — June 26, 1893. An apple- 
tree branch was sprayed with Paris green, in the proportion 
of 1 lb. to 150 gal. of water, and nine fourth-molt cater- 
pillars placed upon it. July 16, the branch having been 
broken off by the wind, the caterpillars were transferred to 
another tree, and the branch sprayed. Five died before 
pupating, and, of the four which pupated, two emerged. 
Foliage badly burned. 

No. 34.— July 10, 1894. Ten caterpillars, of the fifth 



426 THE GYPSY MOTH. 

molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1 lb. to 150 gal. of 
water. One died the fourth day ; three died and one pu- 
pated the sixth day ; two died the ninth, one the tenth, one 
the eleventh and one the twelfth day. 

Check experiment : one died the second day ; two pupated 
the sixth, one the seventh, one the ninth and one the tenth 
day. 

No. 35 (field experiment). —July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 1 lb. to 150 gal. of water. Two pupated the fourteenth, 
two the sixteenth and three the eighteenth day ; one died 
the nineteenth and two pupated the twentieth day. 

No. 36 (field experiment). — June 26, 1893. A branch 
of apple tree was sprayed with Paris green, in the propor- 
tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater- 
pillars were placed upon it. Of these, six died before pu- 
pating ; four pupated, three of which emerged. For some 
reason the foliage appeared to be quite badly burned, 
although the Paris green was in the proportion commonly 
used for spraying. 

No. 37 (field experiment). — June ^G, 1893. A branch 
of apple tree was sprayed with Paris green, in the propor- 
tion of 1 lb. to 150 gal. of water, and ten fifth-molt cater- 
pillars placed upon it. In this experiment the poison took 
effect more quickly than in the corresponding experiments, 
all of the caterpillars having died within three weeks. 

No. 38 (field experiment). — July 12, 1893. A branch 
of hop-hornbeam was sprayed with Paris green, in the pro- 
portion of 1 lb. to 150 gal. of water, and ten caterpillars of 
the fifth molt placed upon the branch. July 21, the foliage 
was so badly burned that the caterpillars were transferred 
to a freshly sprayed branch of oak, which was resprayed 
July 27, on account of the rain. Four caterpillars pupated, 
two of which emerged. Foliage of the hop-hornbeam very 
badly burned ; that of the oak burned somewhat less. 

No. 39 (field experiment). — July 12, 1893. Paris green, 
in the proportion of 1 lb. to 150 gal. of water, was allowed 



INSECTICIDES. 427 

to stand for nearly three hours, to determine the difference 
in action between this and the experiments where the poison 
had not been allowed to stand. An oak branch was sprayed 
with this mixture, and ten large fifth-molt caterpillars 
placed upon it. July 21, the branch was resprayed on 
account of heavy rain, and on July 25 the foliage became so 
badly burned that the caterpillars were transferred to a 
freshly sprayed oak branch. Seven of the ten began to 
pupate, but of these only two emerged, and one of those 
was imperfect. Foliage of the first branch was very badly 
burned, while that of the second was in good condition. 

lh lbs. Paris Green to 150 gal. Water. 

No. 40.— April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 1£ lbs. to 150 gal. 
of water. One died on the first, one the second and six the 
third day ; two escaped. 

Check experiment : none dead. 

No. 41. — May 9, 1894*. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of li lbs. to 150 gal. of 
water. Five died the second, three the third and two the 
fourth day. 

Check experiment : none dead. 

No. 42. —May 28, 1895. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 1| lbs. to 150 gal. of 
water. Four died the third, three the fourth and three the 
fifth day. 

Check experiment : one died the fourth day. 

No. 43. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 1^ lbs. to 150 gal. of 
water. Two died the second, one the third, one the fourth, 
one the fifth, two the sixth, two the seventh and one the 
eighth day. 

Check experiment : none dead. 

No. 44. — June 21, 1894. Ten caterpillars, of the third 



428 THE GYPSY MOTH. 

molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1£ lbs. to 150 gal. 
of water. Two died the third, two the fourth, three the 
fifth, one the sixth and two the seventh day. 

Check experiment : none dead. 

No. 45. — June 29, 1895. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 1£ lbs. to 150 gal. 
of water. Two died the second, four the third, three the 
fourth and one the fifth da}'. 

Check experiment : one died the fourth day. 

No. 46 (field experiment). — June 26, 1893. An apple- 
tree branch was sprayed with Paris green, in the proportion 
of 1£ lbs. to 150 gal. of water, and eight fourth-molt cater- 
pillars placed upon it. Six caterpillars in this experiment 
died gradually, one lived over ten weeks on the foliage and 
pupated. Another lived on the foliage a month, then pu- 
pated and finally emerged. Foliage somewhat burned. 

No. 47 (field experiment) . — June 26, 1893. An apple- 
tree branch was sprayed with Paris green, in the proportion 
of 1£ lbs. to 150 gal. of water, and ten fourth-molt cater- 
pillars placed upon it. Of these, all but one died before 
beginning to pupate, and that one was not able to complete 
the process. It took more than a week for the poison to 
begin to act, and the last caterpillar lived over six weeks. 
The foliage was badly burned. 

No. 48^— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of l^lbs. to 150 gal. of 
water. Two died and one pupated the third day ; one died 
the fourth, two the sixth, three the eighth and one the 
twelfth day. 

Check experiment : one died the second day ; one pupated 
the fourth, one the fifth, one the sixth and one the seventh 
day. 

No. 49 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on a willow branch 
which had been sprayed with Paris green, in the proportion 
of 1| lbs. to 150 gal. of water. One died and one pupated 




PLATE 65. White pine and other trees stripped by the cater- 
pillars of the gypsy moth. 



INSECTICIDES. 429 

the seventh day; one died the thirteenth day; one died and 
two pupated the fourteenth day ; two pupated the eighteenth, 
one the twenty-seventh and one the thirty-first day. 

No. 50 (field experiment). — June 26, 1893. An apple- 
tree branch was sprayed with Paris green, in the proportion 
of 1£ lbs. to 150 gal. of water, and ten fifth-molt cater- 
pillars placed upon it. By the 5th of August all had died, 
none having completed the process of pupation, although 
two or three had begun. The foliage was badly burned. 

No. 51 (field experiment). — June 26, 1893. An apple- 
tree branch was sprayed with Paris green, in the proportion 
of 1J lbs. to 150 gal. of w r ater, and ten fifth-molt cater- 
pillars placed upon it. Of these caterpillars, six died with- 
out pupating ; three began to pupate, but died later ; and 
one pupated and emerged. The foliage was badly burned. 

No. 52 (field experiment). — July 14, 1893. An oak 
branch was sprayed with Paris green, in the proportion of 
1£ lbs. to 150 gal. of water, and ten fifth-molt caterpillars 
placed upon it. On July 20, the branch was resprayed on 
account of rain. Seven of the caterpillars pupated, four 
of which emerged. Three of these seven began pupating 
before they had time to eat any of the poisoned food. 
Foliage badly burned. 

2 lbs. Paris Green to 150 gal. Water. 

No. 53. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 2 lbs. to 150 gal. of 
water. Two died the first, one the second, six the third 
and one the fourth day. 

Check experiment : none dead. 

No. 54. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of 2 lbs. to 150 gal. of water. 
One died the second, four the third, one the fifth and four 
the sixth day. 

Check experiment : none dead. 

No. 55.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 



430 THE GYPSY MOTH. 

with Paris green, in the proportion of 2 lbs. to 150 gal. of 
water. Five died the third, two the fourth, one the sixth, 
one the seventh and one the ninth day. 

Cheek experiment : one died the fourth day. 

No. 56. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 2 lbs. to 150 gal. of 
Avater. One died the second, two the third, one the fourth, 
four the seventh and two the eighth day. 

Check experiment : none dead. 

No. 57. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 2 lbs. to 150 gal. of 
water. One died the second, one the third, four the fifth, 
two the sixth and two the seventh day. 

Check experiment : one died the seventh day. 

No. 58. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 2 lbs. to 150 gal. of 
water. Two died the second, five the third, one the fourth, 
fifth and sixth days. 

Check experiment : one died the fourth and one the sixth 
day. 

No. 59.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 2 lbs. to 150 gal. 
of water. One pupated the fifth day ; two died and four 
pupated the sixth day ; one pupated the seventh day ; one 
died the tenth and one the fourteenth day. 

Check experiment : four pupated and one died the fourth 
day ; one pupated the fifth day, one the sixth, one the ninth 
and one the eleventh day. 

No. 60 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 2 lbs. to 150 gal. of water. One pupated the fourth and 
one died the thirteenth day ; three pupated the fourteenth 
and one died the seventeenth day ; two pupated the nine- 
teenth and two the twenty-sixth day. Foliage badly burned. 



INSECTICIDES. 431 



3 lbs. Paris Green to 150 gal. Water. 

No. 61. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 3 lbs. to 150 gal. of 
water. Five died the second, four the third and one the 
fifth day. 

Check experiment : none dead. 

No. 62. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of 3 lbs. to 150 gal. of water. 
Two died the second, one the third, three the fourth, one 
the fifth and three the sixth day. 

Check experiment : none dead. 

No. 63. — May 2S, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 3 lbs. to 150 gal. of 
water. Eight died the third day, one the seventh and one 
the eighth day. 

Check experiment : none dead. 

No. 64. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 3 lbs. to 150 gal. of 
water. One died the second day, one the third, four the 
fifth, three the seventh and one the ninth day. 

Check experiment : none dead. 

No. 65. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 3 lbs. to 150 gal. 
of water. One died the second, two the third, two the 
fourth, four the fifth and one the sixth day. 

Check experiment : none dead. 

No. 6Q. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 3 lbs. to 150 gal. of 
water. Two died the first, one the second, three the third, 
two the fourth and two the sixth day. 

Check experiment : none dead. 

No. 67. — July 10, 1894. Ten caterpillars, of the fifth 



432 THE GYPSY MOTH. 

molt, were placed on elm leaves which had been sprayed 
with Paris green in the proportion of 3 lbs. to 150 gal. of 
water. One died and one pupated the third day ; one 
pupated the fourth and one the fifth day ; one pupated and 
one died the sixth day ; one died the seventh, two the ninth 
and one the fourteenth day. 

Check experiment : three pupated the fourth day, one 
pupated and one died the sixth clay ; one pupated and one 
died the ninth day ; three died the fourteenth day. 

No. 68 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 3 lbs. to 150 gal. of water. One died the third, one 
the fourth and one the fifth day ; one pupated the sixth, one 
the fifteenth, one the eighteenth, one the twenty-first, one the 
twenty-fourth, one the twenty-eighth and one the thirty- 
first day. Foliage badly burned. 

4 lbs. Paris Green to 150 gal. Water. 

No. 69. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 4 lbs. to 150 gal. of 
water. Five died the second and four the third day ; and 
one escaped. 

Check experiment : none dead. 

No. 70. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of 4 lbs. to 150 gal. of water. 
Two died the second, five the third, one the fourth and one 
the fifth day ; and one escaped. 

Check experiment : two died the fourth day. 

No. 71. — May 28, 1895. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 4 lbs. to 150 gal. of 
water. One died the fourth, two the fifth and seven the 
sixth day. 

Check experiment : one died the fifth day. 

No. 72.— June 10, 1894. Ten caterpillars, of the 
second molt, were placed on elm leaves which had been 



INSECTICIDES. 433 

sprayed with Paris green, in the proportion of 4 lbs. to 150 
gal. of water. Two died the second, three the fourth, two 
the fifth, two the sixth and one the eighth day. 

Check experiment : none dead. 

No. 73. —June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 4 lbs. to 150 gal. of 
water. Four died the second, four the third, one the fifth 
and one the sixth day. 

Check experiment : none dead. 

No. 74. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 4 lbs. to 150 gal. of 
water. Four died the third day ; two pupated the fourth 
day ; three died the fifth and one the sixth day. 

Check experiment : one died the third day. 

No. 75.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 4 lbs. to 150 gal. of 
water. One died the second day, two pupated and two died 
the third day ; two pupated and one died the sixth day ; one 
died the seventh and one the eighth day. 

Check experiment : one pupated the fourth day ; one died 
the sixth day. 

No. 76 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 4 lbs. to 150 gal. of water. One died and two pupated 
the fifth day ; one died the sixth and two the seventh day ; 
one pupated the fourteenth, one the fifteenth, one the nine- 
teenth and one the twenty-second day. Foliage badly 
burned. 

5 lbs. Paris Green to 150 gal. Water, 

No. 77. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Two died the first and seven the third day ; and one 
escaped. 

Check experiment : none dead ; one escaped. 



434 THE GYPSY MOTH. 

No. 78. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green, in the proportion of 5 lbs. to 150 gal. of water. 
One died the first, three the second, two the third, three the 
fourth and one the fifth day. 

Check experiment : one died the second day. 

No. 79.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Five died the third, three the fourth and two the 
sixth day. 

Check experiment : one died the third day. 

No. 80. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Two died the second, three the third, one the fourth, 
one the fifth, one the sixth, one the seventh and one the 
eighth day. 

Check experiment : none dead. 

No. 81. —June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Six died the second and four the third day. 

Check experiment : none dead. 

No. 82.— June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Two died the second, two the third and two the 
fourth day ; one died and one pupated the fifth day ; two 
died the eighth day. 

Check experiment : one died the third day ; one pupated 
the fourth day ; two died the fifth day. 

No. 83.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 5 lbs. to 150 gal. of 
water. Two died the third day ; two pupated the sixth and 
one the seventh day ; one pupated and one died the eighth 
day ; two died the ninth day ; one pupated the eleventh 
day. 



INSECTICIDES. 435 

Check experiment : five pupated the fourth and one the 
fifth day ; one died the eleventh day. 

No. 84 (field experiment) . — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 5 lbs. to 150 gal. of water. One pupated the fourth, 
three the seventh, one the thirteenth, three the fourteenth, 
one the seventeenth and one the twenty-first day. Foliage 
badly burned. 

6 lbs. Paris Green to 150 gal. Water. 
No. 85. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. One died the first, six the second and three the third 
day. 

Check experiment : none dead ; one escaped. 

No. 86. — May 9, 1894. Ten caterpillars, six days old, 

were placed on lettuce leaves which had been treated with 

Paris green, in the proportion of 6 lbs. to 150 gal. of water. 

Five died the second, one the third and four the fourth day. 

Check experiment : none dead. 

No. 87.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. Four died the third, three the fourth, one the fifth, 
one the seventh and one the eighth day. 

Check experiment : one died the fourth day. 
No. 88. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. Four died the first, one the second, two the fourth, 
one the fifth and one the sixth day ; one was lost. 
Check experiment : none dead. 

No. 89. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. Five died the second, two the third, two the fifth 
and one the sixth day. 

Check experiment : none dead. 



436 THE GYPSY MOTH. 

No. 90. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. Four died the first, two the second, one the third, 
fourth, fifth and sixth days. 

Check experiment : one died the third day. 

No. 91.— July 10, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green, in the proportion of 6 lbs. to 150 gal. of 
water. Two died the third day ; one died and one pupated 
the fourth day ; two died and one pupated the sixth day ; 
two died the eighth and one the twelfth day. 

Check experiment : one pupated the fifth day ; one died 
the seventh day ; two died and tw r o pupated the eighth day ; 
one pupated the ninth and one the tenth day. 

No. 92 (field experiment) . — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green, in the proportion 
of 6 lbs. to 150 gal. of water. Two died the fourth, one 
the sixth and one the seventh day ; one pupated the eighth 
and one the thirteenth day ; one died the fourteenth day ; 
one pupated the fifteenth, one the nineteenth and one the 
twentieth day. Foliage badly burned. 

Experiments with Paris Green and Lime. 
\ lb. Each of Paris Green and Lime to 150 gal. Water. 

No. 1. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of £ lb. each 
to 150 gal. of water. One died the second and nine the 
third day. 

Check experiment : none dead. 

No. 2. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of £ lb. each to 150 
gal. of water. One died the second, one the third, seven 
the fifth and one the sixth day. 

Check experiment : none dead. 

No. 3.— May 28, 1894. Ten caterpillars, of the first 



INSECTICIDES. 437 

molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of £ 11). each 
to 150 gal. of water. Three died the third, two the fourth, 
two the sixth, one the seventh and two the eighth day. 

Check experiment : none dead. 

No. 4. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been treated with 
Paris green and lime, in the proportion of £ lb. each to 150 
gal. of water. One died the fourth, one the sixth, four the 
ninth, two the tenth and two the eleventh day. 

Check experiment : none dead. 

No. 5. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of £ lb. each 
to 150 gal. of water. One died the fourth, four the sixth 
and five the seventh day. 

Check experiment : none dead. 

No. 6. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of £ lb. each 
to 150 gal. of water. Two died the first, one the second, 
fourth, fifth, sixth and seventh and three the eighth day. 

Check experiment : one pupated the sixth day. 

No. 7.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of £ lb. each 
to 150 gal. of water. One died the first day; one died and 
one pupated the second day ; two pupated the third day ; 
one died the fifth, one the eighth, one the ninth and two the 
tenth day. 

Check experiment : two pupated the fifth day ; one died 
and one pupated the eighth day ; one pupated the ninth day. 

No. 8 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of £ lb. each to 150 gal. of water. One died the 
fourth, one the fifth and one the seventh day ; one pupated 
the tenth, one the fourteenth, one the sixteenth and four the 
eighteenth day. 



438 THE GYPSY MOTH. 



I lb. Each Paris Green and Lime to 150 gal. Water. 

No. 9. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of | lb. each 
to 150 gal. of water. Two died the second, six the third 
and two the fourth day. 

Check experiment : none dead. 

No. 10. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of | lb. each to 150 
gal. of water. Two died the second, live the third and three 
the fourth day. 

Check experiment : none dead. 

No. 11.— May 2, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of | lb. each 
to 150 gal. of water. One died the third, one the fifth, four 
the seventh, two the eighth and two the ninth day. 

Check experiment : none dead. 

No. 12. — June 10, 1895. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of | lb. each 
to 150 gal. of water. Two died the sixth, six the seventh 
and two the eighth day. 

Check experiment : none dead. 

No. 13. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of | lb. each to 
150 gal. of water. Four died the fifth, one the sixth, four 
the seventh and one the eighth day. 

Check experiment : none dead. 

No. 14. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of ^ lb. each 
to 150 gal. of water. One died the third, five the fourth, 
one the fifth, two the sixth and one the seventh day. 

Check experiment : one died the fourth day. 

No. 15. —July 11, 1894. Ten caterpillars, of the fifth 



INSECTICIDES. 439 

molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of | lb. each 
to 150 gal. of water. Two died the first day; two pupated 
the fifth day ; three died the ninth, two the tenth and one 
the fourteenth day. 

Check experiment :• one lost and one pupated the third 
day; one pupated the fourth, one the fifth and one the 
sixth day; one died the eighth, three the twelfth and one 
the thirteenth day. 

No. 16 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of f lb. each to 150 gal. of water. Two died the 
third day ; two pupated the sixth and one the thirteenth 
day ; one died and one pupated the fourteenth day ; one 
died and two pupated the eighteenth day. 

1 lb. Each Paris Oreen and Lime to 150 gal. Water. 

No. 17. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 1 lb. each 
to 150 gal. of water. Eight died the second, one the fourth 
and one the fifth day. 

Check experiment : none dead ; five escaped. 

No. 18. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 1 lb. each to 150 
gal. of water. One died the second, six the third, one the 
fourth, one the fifth and one the sixth day. 

Check experiment : one died the second day. 

No. 19. — May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 1 lb. each to 
150 gal. of water. One died the fourth, two the fifth, three 
the sixth, two the eighth, one the ninth and one the tenth day. 

Check experiment : one died the sixth day. 

No. 20. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1 lb. each 



440 THE GYPSY MOTH. 

to 150 gal. water. One died the second, four the sixth, four 
the seventh and one the tenth day. 
Check experiment : none dead. 

No. 21. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1 lb. each 
to 150 gal. of water. One died the third, two the fifth, two 
the sixth and five the seventh day. 

Check experiment : one died and one lost the seventh day. 
No. 22. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1 lb. each 
to 150 gal. of water. Three died the second, two the third 
and one the fourth, fifth, sixth, seventh and eighth days. 
Check experiment : one died the third day. 
No. 23.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1 lb. each to 
150 gal. of water. One died and one pupated the second 
day ; two pupated the fourth, two the fifth and one the 
eighth day ; two died the tenth and one the fourteenth day. 
Check experiment : one died and one pupated the third 
day ; one died the seventh, one the eighth and one the tenth 
day. 

No. 24 (field experiment). — Ten caterpillars, of the fifth 
molt, were placed on willow branches which had been sprayed 
with Paris green and lime, in the proportion of 1 lb. each to 
150 gal. of water. One died the sixth and three the seventh 
day ; one pupated the eleventh, one the twelfth, two the thir- 
teenth, one the fifteenth and one the seventeenth day. 

lh lbs. Each Paris Green and Lime to 150 gal. Water. 

No. 25. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 1 J lbs. each 
to 150 gal. of water. Five died the second, two the third 
and one the fourth day, and two escaped. 

Check experiment : one died the fifth day, and five es- 
caped. 



INSECTICIDES. 441 

No. 26. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 1£ lbs. each to 
150 gal. of water. Four died the second, live the third and 
one the fourth day. 

Check experiment : one died the second day. 

No. 27.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 1£ lbs. each 
to 150 gal. of water. Four died the third, one the fourth, 
two the fifth and three the sixth day. 

Check experiment : one died the fifth day. 

No. 28. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves w T hich had been sprayed 
with Paris green and lime, in the proportion of 1^ lbs. each 
to 150 gal. of water. One died the second, one the fourth, 
four the sixth, three the seventh and one the eighth day. 

Check experiment : none dead. 

No. 29.— June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1£ lbs. each 
to 150 gal. of water. Three died the third, one the fourth, 
four the fifth and two the sixth day. 

Check experiment : none dead. 

No. 30. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 1£ lbs. each 
to 150 gal. of water. Four died the third, two the fourth, 
two the fifth and two the sixth day. 

Check experiment : one pupated the fourth day. 

No. 31.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of H lbs. each 
to 150 gal. of water. Two pupated the third and one the 
fifth day ; two died and one pupated the seventh day ; one 
died the eighth, two the ninth and one the eleventh day. 

Check experiment : one died the third day ; one pupated 
the fourth, two the fifth, one the eighth and one the tenth 
day. 



442 THE GYPSY MOTH. 

No. 32 (field experiment) .— July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 1£ lbs. each to 150 gal. of water. One died 
the fourth day ; one died and one pupated the seventh day ; 
one pupated the ninth, one the thirteenth, one the sixteenth, 
two the eighteenth, one the twenty-sixth and one the twenty- 
eighth day. 

2 lbs. Each Paris Green and Lime to 150 gal. Water. 

No. 33. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 2 lbs. each 
to 150 gal. of water. Three died the second, four the third 
and three the fourth day. 

Check experiment : none dead. 

No. 34. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 2 lbs. each to 
150 gal. of water. One died the second, five the third, two 
the fourth and two the fifth day. 

Check experiment : none dead. 

No. 35.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 2 lbs. each 
to 150 gal. of water. One died the third, one the fourth, 
one the fifth, two the sixth, four the seventh and one the 
eighth day. 

Check experiment : none dead. 

No. 36. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 2 lbs. each 
to 150 gal. of water. One died the second, one the fourth, 
two the fifth, three the sixth and three the seventh day. 

Check experiment : none dead. 

No. 37. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 2 lbs. each 
to 150 gal. of water. Two died the second, two the third, 
one the fifth, three the sixth and two the seventh day. 



INSECTICIDES. 443 

Check experiment : two lost the seventh day. 

No. 38. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 2 lbs. each 
to 150 gal. of water. Two died the second, two the third, 
two the fourth, two the fifth, one the sixth and one the 
eighth day. 

Check experiment : one died the fourth, one the fifth and 
one the sixth day. 

No. 39.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 2 lbs. each to 
150 gal. of water. Two pupated the second day; one died 
the third day ; one died and one pupated the fifth day ; one 
pupated the sixth day ; one died the seventh, one the ninth 
and two the tenth day. 

Check experiment : one died the third day ; two died and 
two pupated the ninth day. 

No. 40 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 2 lbs. each to 150 gal. of water. One pupated 
the sixth day ; two died the seventh day ; one pupated the 
eighth day ; one died and one pupated the thirteenth day ; 
one pupated the fourteenth, one the sixteenth, one the 
twentieth and one the twenty-second day. 

3 lbs. Each Paris Green ayd Lime to 150 gal. Water. 

No. 41. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. Four died the second, two the third, 
one the fourth and three the fifth day. 

Check experiment : none dead. 

No. 42. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 3 lbs. each to 150 
gal. of water. Two died the second, three the third, one 
the fourth and four the fifth day. 



444 THE GYPSY MOTH. 

Check experiment : none dead. 

No. 43. — May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. One died the third, three the fifth, 
four the sixth and two the seventh day. 

Check experiment : none dead. 

No. 44. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. One died the second, two the third, 
one the fourth, two the fifth, three the sixth and one the 
seventh day. 

Check experiment : none dead. 

No. 45. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. Five died the third, two the sixth and 
three the seventh day. 

Check experiment : two died the seventh day. 

No. 46. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. Two died the first, one the second, 
two the third, one the fourth, one the fifth, two the sixth 
and one the seventh day. 

Check experiment : none dead. 

No. 47.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 3 lbs. each 
to 150 gal. of water. Two pupated the second and one the 
third day ; two died the seventh and four the ninth day ; 
one pupated the eleventh day. 

Check experiment : one died the third day ; two pupated 
the fifth day ; one died the eighth and one the tenth day. 

No. 48 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 3 lbs. each to 150 gal. of water. One died 
the fourth and two the fifth day ; two died and one pupated 



INSECTICIDES. 445 

the seventh day ; one pupated the tenth, one the fourteenth, 
one the fifteenth and one the twenty-first day. 

4 lbs. Each Paris Green and Lime to 150 gal Water. 

No. 49. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 4 lbs. each 
to 150 gal. of water. Six died the second and four the third 
day. 

Check experiment : none dead. 

No. 50. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 4 lbs. each to 150 
gal. of water. Five died the second, four the third and one 
the fifth day. 

Check experiment : none dead. 

No. 51.— May 28, 1894. Ten caterpillars, of the fifth 
molt, were placed on lettuce leaves which had been treated 
w r ith Paris green and lime, in the proportion of 4 lbs. each 
to 150 gal. of water. Three died the fourth, three the fifth, 
three the sixth and one the seventh day. 

Check experiment : none dead. 

No. 52. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 4 lbs. each 
to 150 gal. of water. One died the third, two the fourth, 
three the fifth and four the seventh day. 

Check experiment : none dead. 

No. 53. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 4 lbs. each 
to 150 gal. of water. Three died the second, four the third, 
one the fifth and two the sixth day. 

Check experiment : none dead. 

No. 54. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which were sprayed with 
Paris green and lime, in the proportion of 4 lbs. each to 150 
gal. of water. One died the first, one the second, two the 
third, four the fourth and two the fifth day. 

Check experiment : none dead. 



446 THE GYPSY MOTH. 

No. 55.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 4 lbs. each 
to 150 gal. of water. Three pupated the second day ; one 
died the third, one the fourth, one the fifth, two the sixth, 
one the seventh and one the eighth day. 

Check experiment : two pupated the third, one the fourth 
and one the sixth day. 

No. 56 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 4 lbs. each to 150 gal. of water. One died 
the fourth, one the fifth, one the sixth and one the seventh 
day ; one pupated the ninth day ; one died and one pupated 
the tenth day ; one pupated the thirteenth, one the seven- 
teenth and one the eighteenth day. 

5 lbs. Each Paris Green and Lime to 150 gal. Water. 

No. 57. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 5 lbs. each 
to 150 gal. of water. One died the first, two the second and 
five the third day ; and two escaped. 

Check experiment : none dead. 

No. 58. — May 9, 1895. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 5 lbs. each to 150 
gal. of water. One died the second, one the third, five the 
fourth and three the fifth day. 

Check experiment : none dead. 

No. 59.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 5 lbs. each 
to 150 gal. of water. Two died the third, one the fourth, 
two the fifth, three the sixth and two the eighth day. 

Check experiment : none dead. 

No. 60. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 5 lbs. each 



INSECTICIDES. 447 

to 150 gal. of water. Four died the second, one the third, 
two the fourth, two the fifth and one the sixth day. 

Check experiment : none dead. 

No. 61. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 5 lbs. each 
to 150 gal. of water. Two died the second, one the third, 
two the fourth, two the sixth, two the seventh and one the 
eighth day. 

Check experiment : one died the seventh day. 

No. 62. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 5 lbs. each 
to 150 gal. of water. Two died the second, four the third, 
three the fourth and one the sixth day. 

Check experiment : none dead. 

No. 63.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which 'had been sprayed 
with Paris green and lime, in the proportion of 5 lbs. each 
to 150 gal. of water. Two pupated and two died the second 
day ; one died and one pupated the third day ; one died the 
seventh and three the eighth day. 

Check experiment : two pupated the third day ; one died 
and three pupated the fifth day ; one pupated the eighth 
day. 

No. 64 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 5 lbs. each to 150 gal. of water. One died the 
fourth, one the fifth, one the sixth and one the seventh day ; 
two died and one pupated the eighth da} 7 ; one pupated and 
one was lost the fourteenth day ; one pupated the thirty- 
third day. 

6 lbs. Each Paris Green and Lime to 150 gal. Water. 

No. 65. — April 26, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 6 lbs. each 
to 150 gal. of water. Six died the second, three the third 
and one the fourth day. 



448 THE GYPSY MOTH. 

Check experiment : none dead. 

No. 66. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
Paris green and lime, in the proportion of 6 lbs. each to 150 
gal. of water. One died the second, three the third, three 
the fourth and three the fifth day. 

Check experiment : one died the third day. 

No. 67. — May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with Paris green and lime, in the proportion of 6 lbs. each 
to 150 gal. of water. Six died the third, two the fourth, 
one the fifth and one the sixth day. 

Check experiment : none dead. 

No. 68. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been treated with 
Paris green and lime, in the proportion of 6 lbs. each to 150 
gal. of water. Three died the second, three the third, two 
the fifth, one the sixth and one the seventh day. 

Check experiment : none dead. 

No. 69. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed with 
Paris green and lime, in the proportion of 6 lbs. each to 150 
gal. of water. Two died the second, one the third, two the 
fourth, one the sixth and four the seventh day. 

Check experiment : one accidentally killed the seventh day. 

No. 70. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 6 lbs. each to 
150 gal. of water. Six died the second, two the third and 
two the fourth clay. 

Check experiment • one died the third day. 

No. 71.— July 11, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with Paris green and lime, in the proportion of 6 lbs. each to 
150 gal. of water. One died the first day; one died and 
two pupated the second day; one died the third day; one 
pupated the filth day ; three died the seventh and one the 
eleventh day. 

Check experiment : one pupated the third day ; one died 
and four pupated the fifth day ; one died the tenth day. 



INSECTICIDES. 449 

No. 72 (field experiment). — July 7, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with Paris green and lime, in the 
proportion of 6 lbs. each to 150 gal. of water. One died 
the fourth, one the sixth, two the seventh and one the eighth 
day ; one pupated the fourteenth, one the fifteenth, one the 
sixteenth and two the eighteenth day. 

Experiments with Arsenate of Lead, 

\ lb. Arsenate of Lead to 150 gal. Water. 

No. 1. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of ^ lb. to 150 gal. 
of water. One died the fifth, one the sixth and one the 
seventh day ; those remaining lived and molted. 

No. 2. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves, which had been treated with 
arsenate of lead, in the proportion of -J lb. to 150 gal. of 
water. One died the fifth day ; those remaining lived and 
molted. 

Check experiment : none dead. 

No. 3. — May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of £ lb. to 150 gal. 
of water. All lived through the experiment. 

Check experiment : none dead. 

No. 4. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of ^ lb. to 150 gal. 
of water. All lived through the experiment. 

Check experiment : none dead. 

No. 5. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of \ lb. to 150 gal. 
of water. One died the seventh, three the eighth and one 
the ninth daj r ; one pupated the tenth day ; one died the 
eleventh day. The remainder lived through the experiment. 

Check experiment : one was lost the seventh day ; one 
pupated the eighth day ; two died the tenth day. 



450 THE GYPSY MOTH. 



\ lb. Arsenate of Lead to 150 gal. Water. 

No. 6. — March 7, 1894. Ten caterpillars, three days 
old, were placed upon lettuce leaves which had been treated 
with arsenate of lead, in the proportion of \ lb to 150 gal. 
of water. On the ninth day six were dead and four lost. 

No. 7. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of \ lb. to 150 gal. of 
water. All lived through the experiment (seventeen days). 

Check experiment : none dead. 

No. 8. -May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of \ lb. to 150 gal. 
of water. One died the third, one the fourth, one the 
seventh and one the ninth day ; the remainder lived through 
the experiment. 

Check experiment : none dead. 

No. 9. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of £ lb. to 150 gal. 
of water. One died the fifth and two the eleventh day ; the 
remainder lived through the experiment. 

Check experiment : none dead. 

No. 10. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves "which had been sprayed 
with arsenate of lead, in the proportion of \ lb. to 150 gal. 
of water. One died the fourth, one the fifth and one the 
sixth, two died and one pupated the seventh, two died the 
eighth, one the tenth and one the eleventh day. 

Check experiment : one died the seventh and one the 
ninth day ; one was lost the tenth day. 

No. 11 (field experiment). — June 29, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of \ lb. to 150 gal. of water, and nine fourth-molt caterpil- 
lars placed upon it. July 31, for lack of food, they were 
transferred to a fresh branch, which was left unsprayed. All 
these caterpillars pupated and six emerged. Foliage unin- 
jured. 

No. 12 (field experiment). — June 29, 1893. A branch 



INSECTICIDES. 451 

of oak was sprayed with arsenate of lead, in the proportion 
of 1 lb. to 150 gal. of water, and ten caterpillars, of the 
fourth molt, were placed upon it. Three of these died before 
pupating, the last one dying thirty-seven days after the first 
spraying. Of the seven that pupated, all emerged. Foliage 
uninjured. 

No. 13 (field experiment). — June 29, 1893. A branch 
of a small oak was sprayed with arsenate of lead, in the 
proportion of \ lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 20, the branch was re- 
sprayed on account of the rain on the 18th. Only one cater- 
pillar died before pupating, and seven were able to complete 
the process of pupation and emerge. Another one fed on 
the leaves for nine days after the spraying and pupated, but 
was injured in removing, and therefore not counted in the 
above summary. Foliage uninjured. 

No. 14 (field experiment). — June 29, 1893. A branch 
of a small oak tree was sprayed with arsenate of lead, in the 
proportion of ^ lb. to 150 gal. of water, and nine fifth-molt 
caterpillars were placed upon it. July 20, the branch was 
resprayed on account of rain. Only one caterpillar died 
before pupating, and that on the forty-first day after the first 
spraying. Of the eight that pupated, two died without 
emerging. Foliage uninjured. 

i lb. Arsenate of Lead to 150 gal. Water. 

No. 15. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of \ lb. to 150 gal. 
of water. On the eighth day all were dead. 

No. 16. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of £ lb. to 150 gal. of 
water. One died the fifth day ; the remainder lived through 
the experiment and molted. 

Check experiment : none dead. 

No. 17.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of £ lb. to 150 gal. 
of water. One died the third, one the fourth, two the fifth, 



452 THE GYPSY MOTH. 

one the tenth and one the eleventh day ; the remainder lived 
through the experiment. 

Check experiment : none dead. 

No. 18. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of £ lb. to 150 gal. 
of water. Two died the fifth, one the seventh, three the 
eighth, two the ninth, one the tenth and one the twelfth day. 

Check experiment : none dead. 

No. 19. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed with 
arsenate of lead, in the proportion of £ lb. to 150 gal. of 
water. Two died the third, three the seventh, two the 
eighth, one the tenth and two the twelfth day. 

Check experiment : two died the seventh and one the 
eighth day ; two were lost. 

No. 20 (field experiment) .— June 28, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of £ lb. to 150 gal. of water, and ten fourth-molt 
caterpillars placed upon it. On the 19th of July, the food 
having given out and two of the caterpillars having died, 
those remaining were transferred to a freshly sprayed branch. 
Of the ten, two died before pupating, and of the eight that 
pupated, five emerged. Foliage uninjured. 

No. 21 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam w T as sprayed with arsenate of lead, in the 
proportion of £ lb. to 150 gal. of water, and nine fourth- 
molt caterpillars placed upon it. July 19, as the food supply 
was nearly gone, the caterpillars were removed to a freshly 
sprayed branch. One died before beginning to pupate, and 
of the eight which pupated, six emerged. Foliage unin- 
jured. 

No. 22 (field experiment). — June 29, 1893. A branch 
of a small oak tree was sprayed with arsenate of lead, in the 
proportion of £ lb. to 150 gal. of water, and nine fourth- 
molt caterpillars were placed upon it. July 20, they were 
transferred to a freshly sprayed branch, both on account of 
the food supply and rain. It was noticeable that on the old 
branch the caterpillars had eaten all of the old, tough leaves, 
and left the young and fresh ones. Two died before pupat- 



INSECTICIDES. 453 

ing, and, of the seven that pupated, four emerged. Foliage 
uninjured. 

No. 23 ( field experiment). — June 29, 1893. An oak 
branch was sprayed with arsenate of lead, in the proportion 
of ^ lb. to 150 gal. of water, and ten fourth-molt caterpillars 
were placed upon it. July 20, the branch was resprayed on 
account of rain. One died before pupating, and eight of 
the nine that pupated emerged. Foliage uninjured. 

No. 24 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of £ lb. to 150 gal. of water, and nine fifth-molt 
caterpillars placed upon it. On the 19th of July, they were 
removed to a freshly sprayed branch. Of the eight that 
pupated, six emerged. Foliage uninjured. 

No. 25 (field experiment). — June 28, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of *. lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 15, as the food supply was 
getting low, the caterpillars were removed to another branch 
which was not sprayed. Three died before pupating, and, of 
the seven which pupated, six emerged. Foliage uninjured. 

No. 26. — June 29, 1893. An oak branch was sprayed 
with arsenate of lead, in the proportion of ^ lb. to 150 gal. 
of water, and nine fifth-molt caterpillars placed upon it. 
July 5, they were transferred to a freshly sprayed branch. 
Only one of these caterpillars died before beginning to 
pupate, and, of those that pupated, seven emerged. Foliage 
uninjured. 

No. 27 (field experiment). —June 29, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of Jib. to 150 gal. of water, and ten fifth-molt caterpillars 
placed upon it. July 15, for lack of food, they were trans-, 
ferred to a freshly sprayed branch. None of these cater- 
pillars died before pupating, and five emerged. Foliage 
uninjured. 

| lb. Arsenate of Lead to 150 gal. Water. 

No. 28. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of | lb. to 150 gal. 
of water. On the fourth day one died, on the fifth three, on 



454 THE GYPSY MOTH. 

the sixth two and on the seventh three ; the remaining one 
was lost. 

No. 29. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of | lb. to 150 gal. of 
water. All lived through the experiment. 

Check experiment : none dead. 

No. 30.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of | lb. to 150 gal. 
of water. One died the eighth and three the tenth day ; 
those remaining lived through the experiment. 

Check experiment : none dead. 

No. 31. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of f lb. to 150 gal. 
of water. Two died the fifth, one the ninth, one the 
eleventh, two the thirteenth and four the eighteenth day. 

Check experiment : none dead. 

No. 32. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of f lb. to 150 gal. 
of water. One died the third, one the seventh and one the 
ninth day ; one pupated the tenth day ; one died and one 
pupated the eleventh day ; and four died the twelfth day. 

Check experiment : one pupated the tenth day and two 
died the eleventh day. 

No. 33 (field experiment). —June 27, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of f lb. to 150 gal. of water, and nine fourth- 
molt caterpillars placed upon it. Of these, three died before 
pupating, and, of the six which pupated, three emerged. 
Foliage uninjured. 

No. 34 (field experiment). — June 27, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of f lb. to 150 gal. of water, and nine fourth- 
molt caterpillars placed upon it. Of these, seven pupated 
and emerged, one began pupating but died later, and one 
died in the larval stage. Foliage uninjured. 

No. 35 (field experiment). — June 27, 1893. A branch 



INSECTICIDES. 455 

of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of f lb. to 150 gal. of water, and ten caterpillars, 
of the fourth molt, placed upon it. July 8, the foliage was 
so badly burned that the nine remaining caterpillars were 
transferred to a freshly sprayed branch of oak. By the 19th 
of July all were dead. The foliage of the oak was slightly 
burned. 

No. 36 (field experiment). — June 27, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of f lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. All died without pupating. 

No. 37 (field experiment). —June 27, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of f lb. to 150 gal. of water, and nine fifth-molt 
caterpillars placed upon it. Of these, only one completed 
the process of pupation and emerged, three having died 
before beginning to pupa'te. Foliage uninjured. 

1 lb. Arsenate of Lead to 150 gal. Water. 

No. 38. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 
of water. One died the fifth, three the sixth and one the 
seventh day ; and five were lost. 

No. 39. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 1 lb. to 150 gal. of 
water. All lived through "the experiment and molted. 

Check experiment : none dead. 

No. 40.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 
of water. Four died the fourth, one the seventh, one the 
eighth and one the ninth day ; the remainder lived through 
the experiment. 

Check experiment : one died the third and one the seventh 
day. 

No. 41. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 



456 THE GYPSY MOTH. 

of water. One died the second, one the seventh, three the 
ninth, four the tenth and one the eleventh day. 

Check experiment : none dead. 

No. 42. — June 21, 1894. Ten' caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 
of water. One died the fifth, two the sixth, three the seventh 
and four the eighth day. 

Check experiment : one died the seventh and one the 
eighth day. 

No. 43. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 
of water. One died the second, one the third, two the 
fourth and one the fifth, sixth, seventh, eighth, ninth and 
tenth days. 

Check experiment : one lost and one dead the seventh day. 

No. 44 (field experiment). — June 26, 1'893. An apple- 
tree branch was sprayed with arsenate of lead, in the pro- 
portion of 1 lb. to 150 gal. of water, and eight fourth-molt 
caterpillars placed upon it. Of these, only one died before 
pupating, and, of the seven which pupated, three emerged. 
Foliage uninjured. 

No. 45 (field experiment). — June 26, 1893. A branch 
of an apple tree was sprayed with arsenate of lead, in the 
proportion of 1 lb. to 150 gal. of water, and eight fourth- 
molt caterpillars placed upon it. Of these, six died before 
pupating, and, of the two which pupated, one emerged. 
Foliage uninjured. 

No. 46.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 1 lb. to 150 gal. 
of water. One died and one pupated the second day ; one 
died the third, one the fourth, two the fifth, one the seventh, 
tenth, eleventh and sixteenth days. 

Check experiment : one pupated the third day ; one died 
the seventh, eighth, ninth and eleventh days ; two pupated 
the twelfth day ; one died the thirteenth and one the four- 
teenth day ; and one was living at the close of the experi- 
ment. 



INSECTICIDES. 457 

No. 47 (field experiment) . — July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the pro- 
portion of 1 lb. to 150 gal. of water. One pupated the fifth 
and one the sixth day ; one died and one pupated the seventh 
day ; one pupated the twelfth day ; one died the thirteenth, 
one the fifteenth and one the sixteenth day ; one pupated the 
twenty-fourth and one the twenty-eighth day. 

No. 48 (field experiment). — June 26, 1893. An apple- 
tree branch was sprayed with arsenate of lead; in the pro- 
portion of 1 lb. to 150 gal. of water, and eight fifth-molt 
caterpillars placed upon it. Of these, only one died before 
pupating, and, of those that pupated, one died without 
emerging. Foliage uninjured. 

No. 49 (field experiment). — June 26, 1893. An apple- 
tree branch was sprayed with arsenate of lead, in the pro- 
portion of 1 lb. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. One of these died before pupat- 
ing, and, of the remaining nine, eight completed the process 
of pupation and emerged. The foliage was uninjured. 

No. 50 (field experiment). — July 1, 1893. A small oak 
branch was sprayed with arsenate of lead, in the proportion 
of 1 lb. to 150 gal. of water, and ten large fifth-molt cater- 
pillars placed upon it. All died within twelve days after 
spraying. Foliage uninjured. 

1\ lb. Arsenate of Lead to 150 gal. Water. 

No. 51. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 1| lbs. to 150 
gal. of water. One died the fourth, three the fifth, one the 
sixth and one the twelfth day ; those remaining lived 
through the experiment. 

No. 52. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. of 
water. Three died the fifth day ; the remainder lived through, 
the experiment and molted. 

Check experiment : none dead. 

No. 53.— May 28, 1894. Ten caterpillars, of the first 



458 THE GYPSY MOTH. 

molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 1£ lbs. to 150 
gal. of water. One died the third, one the fourth, two the 
fifth, three the sixth and two the ninth day ; the remainder 
lived through the experiment. 

Check experiment : none dead. 

No. 54. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of li lbs. to 150 
gal. of water. One died the fifth, two the sixth, one the 
seventh, two the eighth, three the ninth and one the eleventh 
day. 

Check experiment : none dead. 

No. 55. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed with 
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. of 
water. Two died the third, two the fifth and one the sixth 
day ; one died and one pupated the seventh day ; two died 
the eighth and one the ninth day. 

Check experiment : one died the ninth day. 

No. 56. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed with 
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. of 
water. One died the first, one the second, two the third, 
two the fourth, two the fifth and two the seventh day. 

Check experiment : one pupated the second day ; one died 
the fourth and one the sixth day. 

No. 57 (field experiment). — June 24, 1893. An apple- 
tree branch was sprayed with arsenate of lead, in the pro- 
portion of 1£ lbs. to 150 gal. of water, and nine fourth-molt 
caterpillars placed upon it. Two died before pupating, and, 
of the seven that pupated, one died without emerging. 
Foliage uninjured. 

No. 58.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed with 
arsenate of lead, in the proportion of 1£ lbs. to 150 gal. 
of water. One died and one pupated the fourth day ; one 
died and one pupated the fifth day ; two died the sixth and 
one the seventh day ; one pupated the ninth day ; two died 
the eleventh day. 



INSECTICIDES. 459 

Check experiment : three pupated the fourth and two the 
fifth day ; one died and one pupated the seventh day ; one 
died the eighth day ; and two were living at the close of the 
experiment. 

No. 59 (field experiment). — July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the pro- 
portion of 1£ lbs. to 150 gal. of Mater. One died the fifth 
day ; one pupated the eleventh and one the twelfth day, one 
died the fourteenth day ; one pupated the fifteenth day, one 
died the sixteenth day ; one pupated the eighteenth, one the 
twentieth, one the twenty-first and one the twenty-fourth day. 

No. 60 (field experiment). — June 24, 1893. A branch 
of apple tree was sprayed with arsenate of lead, in the pro- 
portion of 1£ lbs. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 10, one caterpillar having 
pupated and been removed, those remaining were transferred 
to a freshly sprayed apple branch. Only four of the ten 
which pupated emerged. Foliage uninjured. 

2 lbs. Arsenate of Lead to 150 gal. Water. 

No. 61. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. One died the first, four the fourth, two the fifth 
and two the sixth day ; and one was lost. 

No. 62. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 2 lbs. to 150 gal. of 
water. On the fifth day five were dead ; two died the sixth 
and three the seventh day. 

Check experiment : none dead. 

No. 63.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. On the fourth day two died; on the fifth, three ; 
on the sixth, two ; on the seventh, one ; on the eighth, one ; 
and on the eleventh, one. 

Check experiment : one died the sixth day. 

No. 64. — June 10, 1894. Ten caterpillars, of the second 



460 THE GYPSY MOTH. 

molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. One died the second, three the fourth, three the 
fifth, one the sixth, one the seventh and one the tenth day. 

Check experiment : none dead. 

No. 65. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. Four died the third, three the fourth, two the 
sixth and one the seventh day. 

Check experiment : one lost the seventh and one the 
eighth day. 

No. 66. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. Two died the fourth, four the fifth, two the sixth 
and two the seventh day. 

Check experiment : one died and two pupated the second 
day ; two died the third 'day, two the fourth and three the 
fifth day. 

No. 67 (field experiment). — June 21, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of 2 lbs. to 150 gal. of water, and ten fourth- 
molt caterpillars placed upon it. Four of these caterpillars 
began to pupate, and, as the food gave out, those remaining 
were transferred to a branch which had not been sprayed, 
two more pupating after their removal. The other four cater- 
pillars died from the effects of the poison. Foliage uninjured. 

No. 68 (field experiment). — June 24, 1893. A branch 
of apple tree was sprayed with arsenate of lead, in the pro- 
portion of 2 lbs. to 150 gal. of water, and eight fourth-molt 
caterpillars placed upon it. On account of the rain, the 
branch was resprayed twice. One caterpillar pupated, and 
from the pupa a male moth emerged. The rest were all 
dead by the 9th of August. Foliage uninjured. 

No. 69 (field experiment). — June 24, 1893. A branch 
of apple tree was sprayed with arsenate of lead, in the pro- 
portion of 2 lbs. to 150 gal. of water, and nine fourth-molt 
caterpillars placed upon it. Five of the caterpillars died 
before pupating, and, of the four that pupated, three emerged. 



INSECTICIDES. 461 

The poison acted very slowly, as none of the caterpillars 
died for nearly three weeks, and one lived eight weeks. 

No. 70.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 
of water. One died the second da}' ; three died and one 
pupated the fifth day ; one died and one pupated the sixth 
and seventh days ; and one pupated the tenth day. 

Check experiment : two pupated the fourth, three the fifth, 
one the sixth, seventh and eighth days ; and two were living 
at the close of the experiment. 

No. 71 (field experiment).— July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the propor- 
tion of 2 lbs. to 150 gal. of water. One died the first day; 
one pupated the third day ; one died the fourth and one the 
fifth day ; one pupated the eighth and one the twelfth day ; 
one died and one pupated the thirteenth day ; one pupated 
the fifteenth and one the eighteenth day. 

No. 72 (field experiment). — June 21, 1893. A branch 
of a small, hop-hornbeam was sprayed with arsenate of lead, 
in the proportion of 2 lbs. to 150 gal. of water, and ten fifth- 
molt caterpillars were placed upon it. July 14, all were 
dead. In this experiment the caterpillars died gradually, 
the first one dying two days after the poison had been 
applied, the last one living twenty-two days. The foliage 
of the tree was uninjured. 

No. 73 (field experiment) .— June 24, 1893. A branch 
of apple tree was sprayed with arsenate of lead, in the pro- 
portion of 2 lbs. to 150 gal. of water, and nine fifth-molt 
caterpillars placed upon it. In this experiment the poison 
was nearly all washed off by heavy rains soon after it was 
applied. Four of the caterpillars molted and two pupated, 
but all were dead August 2. Foliage uninjured. 

No. 74 (field experiment). — June 24, 1893. A branch 
of apple tree was sprayed with arsenate of lead, in the pro- 
portion of 2 lbs. to 150 gal. of water, and nine fifth-molt 
caterpillars placed upon it. Six of the nine caterpillars died 
before pupating, and, of the three which pupated, only one 
emerged. Foliage uninjured. 



462 THE GYPSY MOTH. 

No. 75 (field experiment). — July 7, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 2 lbs. to 150 gal. of water, and ten caterpillars, of the fifth 
molt, placed upon it. On July 22, and also on the 27th, the 
branch was resprayed on account of rain. In this experi- 
ment only one caterpillar began pupating, and that one was 
not able to complete the process. 

No. 76 (field experiment). — July 7, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 2 lbs. to 150 gal. of water, and ten fifth-molt caterpillars 
placed upon it. Three of these began pupating, and one 
emerged ; but, as this one began to pupate very soon after 
the poison was applied, it probably did not get any ill effect 
from it. Foliage uninjured. 

3 lbs. Arsenate of Lead to 150 gal. Water. 

No. 77. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 
of water. Six died the third, one the fourth and three the 
sixth day. 

No. 78. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 3 lbs. to 150 gal. of 
water. One died the third, three the fourth, two the fifth, 
one the sixth and one the seventh day ; the remainder sur- 
vived. 

Check experiment : none dead. 

No. 79.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 
of water. Two died the fourth, one the fifth, two the sixth, 
one the seventh, three the eighth and one the ninth day. 

Check experiment : one died the sixth day. 

No. 80. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 
of water. One died the fourth, eight the fifth and one the 
sixth day. 

Check experiment : none dead. 



INSECTICIDES. 463 

No. 81. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 
of water. Three died the fourth, five the sixth and two the 
seventh day. 

Check experiment : one died the seventh day. 

No. 82. — June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 
of water. Two died and one pupated the second day ; two 
died the third, two the fourth and three the fifth day. 

Check experiment : two pupated the second and one the 
fifth day. 

No. 83 (field experiment). — June 30, 1893. A branch 
of a small oak tree was sprayed with arsenate of lead, in the 
proportion of 3 lbs. to 150 gal. of water, and seven fourth- 
molt caterpillars placed upon it. The branch was resprayed 
July 20, on account of rain. All of these caterpillars died 
within twenty-five days after the first spraying, and five days 
after the second. Foliage uninjured. 

No. 84 (field experiment). — June 30, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 3 lbs. to 150 gal. of water, and eight fourth-molt cater- 
pillars placed upon it. August 27, all were dead. Foliage 
uninjured. 

No. 85.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on leaves which had been sprayed with 
arsenate of lead, in the proportion of 3 lbs. to 150 gal. of 
water. One died and one pupated the third day ; one 
pupated the sixth day ; three died the seventh day ; one died 
and two pupated the ninth day ; and one pupated the thir- 
teenth day. 

Check experiment: one pupated the fourth, fifth and sixth 
days ; one died the seventh day ; one pupated the eighth and 
two the ninth day ; and one died the eleventh day. 

No. 86 (field experiment). — July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow T branches 
which had been sprayed with arsenate of lead, in the propor- 
tion of 3 lbs. to 150 gal. of water. One died the first and 
one the second day ; one pupated the fifth, two the sixth and 



464 THE GYPSY MOTH. 

two the eighth day ; one died the fourteenth day ; one 
pupated the twenty-fifth and one the twenty-eighth day. 

No. 87 (field experiment). — June 30, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 3 lbs. to 150 gal. of water, and ten caterpillars of the fifth 
molt placed upon it. All died within three weeks, and six 
of the ten in less than one week after the branch was sprayed. 
Foliage uninjured. 

No. 88 (field experiment). — June 30, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 3 lbs. to 150 gal. of water, and ten caterpillars of the fifth 
molt placed upon it. July 20, the branch was resprayed on 
account of rain. Only two of these caterpillars pupated and 
but one emerged. Foliage uninjured. 

4 lbs. Arsenate of Lead to 150 gal. Water. 

No. 89. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. Three died the third, two the fourth and five the 
fifth day. 

No. 90. — May 9, 1895. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 4 lbs. to 150 gal. of 
water. One died the third, two the fourth, five the fifth and 
two the sixth day. 

Check experiment : none dead. 

No. 91. — May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. Two died the third, three the fourth, two the 
fifth and three the seventh day. 

Check experiment : none dead. 

No. 92. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. One died the second, one the third, one the 
fourth, two the fifth, one the sixth, two the seventh and two 
the eighth day. 

Check experiment : none dead. 



INSECTICIDES. 4G5 

No. 93. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. One died the third, one the fourth, two the fifth, 
three the sixth and three the seventh day. 

Check experiment : one died the seventh day. 

No. 94. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. One died the second, five the third, two the 
fourth, one the fifth and one the sixth day. 

Check experiment : one pupated and one died the second 
day ; one pupated the third day ; and one died the fifth day. 

No. 95 (field experiment). — June 21, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of 4 lbs. to 150 gal. of water, and ten fourth-molt 
caterpillars placed upon it. In this experiment eight of the 
ten caterpillars died within nine days ; the other two lived 
twelve and thirteen days longer. Foliage uninjured. 

No. 96.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 4 lbs. to 150 gal. 
of water. One pupated and two died the fourth day, two 
pupated and three died the fifth day ; one died the sixth and 
one the seventh day. 

Check experiment : one died the fourth day. 

No. 97 (field experiment). — July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the propor- 
tion of 4 lbs. to 150 gal. of water. One died and one 
pupated the third day ; one died the fifth and one the sixth 
day ; one pupated the seventh and one the ninth day ; one 
died the eleventh day ; one pupated the twelfth day ; one 
died the fifteenth day ; one pupated the twenty-ninth day. 

No. 98 (field experiment). — June 21, 1893. A branch 
of hop-hornbeam was sprayed with arsenate of lead, in the 
proportion of 4 lbs. to 150 gal. of water, and ten fifth-molt 
caterpillars placed upon it. July 12, all were dead. Al- 
though these were fifth-molt caterpillars, they succumbed to 
the poison much quicker than those of the fourth molt, six 



466 THE GYPSY MOTH. 

dying within a week, and the last one dying in a little over 
two weeks. Foliage uninjured. 

5 lbs. Arsenate of Lead to 150 gal. Water. 

No. 99.— March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 5 lbs. to 150 
gal. of water. One died the first, two the third, one the 
fourth, four the fifth, and one died and one was lost the sixth 
day. 

No. 100.— May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 5 lbs. to 150 gal. of 
water. Four died the third, three the fourth and three the 
fifth day. 

Check experiment : none dead. 

No. 101.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 5 lbs. to 150 gal. 
of water. Three died the fourth, one the fifth, four the sixth 
and two the seventh day. 

Check experiment : none dead. 

No. 102.— June 10, 1894. Ten caterpillars, of the 
second molt, were placed on lettuce leaves which had been 
treated with arsenate of lead, in the proportion of 5 lbs. to 
150 gal. of water. Two died the second, three the fifth, one 
the sixth, three the seventh and one the ninth day. 

Check experiment : none dead. 
, No. 103. —June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been treated 
with arsenate of lead, in the proportion of 5 lbs. to 150 gal. 
of water. Two died the third, two the fourth, one the fifth 
and five the sixth day. 

Check experiment : none dead. 

No. 104.— June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been treated with 
arsenate of lead, in the proportion of 5 lbs. to 150 gal. of 
water. Three died the second, two the third, two the 
fourth, one the fifth and two the sixth day. 

Check experiment : one died and two pupated the second 



INSECTICIDES. 467 

day ; one pupated the third day ; two died the fourth and 
one the fifth day. 

No. 105 (field experiment). — June 21, 1893. A branch 
of oak was sprayed with arsenate of lead, in the proportion 
of 5 lbs. to 150 gal. of water, and ten fourth-molt caterpillars 
placed upon it. July 5, the last one was dead. In this 
experiment five or six days w 7 ere required for the poison to 
take effect ; after that time, however, the caterpillars died 
rapidly. 

No. 106.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 5 lbs. to 150 gal. 
of water. One pupated the third day ; one died the fourth 
and one the fifth day ; one pupated and one died the sixth 
day ; two died the seventh and one the eighth, twelfth and 
thirteenth days. 

Check experiment : one died the third day ; one pupated 
the fifth day ; two died the sixth and one the seventh day ; 
one died and one pupated the eleventh day ; one pupated 
the twelfth day. 

No. 107 (field experiment).— July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been treated with arsenate of lead, in the propor- 
tion of 5 lbs. to 150 gal. of water. One died and one 
pupated the fourth day ; two died the eleventh and two the 
twelfth day ; one pupated the seventeenth, one the nineteenth 
and two the twentieth day. 

6 lbs. Arsenate of Lead to 150 gal. Water. 

No. 108.— March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. One died the first, one the second, three the third, 
four the fourth and one the fifth day. 

No. 109. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 6 lbs. to 150 gal. of 
water. Two died the first, five the third and three the fifth 
day. 

Check experiment : none dead. 



468 THE GYPSY MOTH. 

No. 110. —May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. Two died the third, one the fourth, two the fifth, 
two the sixth and three the eighth day. 

Check experiment : one died the sixth day. 

No. 111. — June 10, 1894. Ten caterpillars, of the second 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. One died the third, two the fourth, three the fifth, 
three the sixth and one the eighth day. 

Check experiment : none dead. 

No. 112. —June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. One died the second, three the third, two the 
fourth, one the fifth, two the sixth and one the seventh day. 

Check experiment : none dead. 

No. 113. —June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. Three died the second, two the third, three the 
fourth and two the sixth day. 

Check experiment : one died and one pupated the second 
day ; one died the third and one the fifth day. 

No. 114 (field experiment). — July 1, 1893. A branch 
of a small oak tree was sprayed with arsenate of lead, in the 
proportion of 6 lbs. to 150 gal. of water, and ten large fifth- 
molt caterpillars placed upon it. All died within three 
weeks from the time of spraying. Foliage uninjured. 

No. 115.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water. Two died and three pupated the fourth day ; 
three died the seventh, one the ninth and one the tenth day. 

Check experiment : one died and two pupated the fourth 
day ; one died the fifth day ; two pupated the sixth and one 
the seventh and eighth days. 

No. 116 (field experiment). — July 9, 1894. Ten cater- 



INSECTICIDES. 469 

pillars, of the fifth molt, were placed on willow branches 
which had been treated with arsenate of lead, in the propor- 
tion of 6 lbs. to 150 gal. of w T ater. One died the second 
day ; one pupated the third day ; two died the fifth, two the 
sixth and one the eleventh day ; one pupated the thirteenth, 
one the sixteenth and one the nineteenth day. 

7 lbs. Arsenate of Lead to 150 gal. Water. 

No. 117. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 7 lbs. to 150 gal. 
of water. Three died the first, three the second and four 
the fifth day. 

No. 118. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 7 lbs. to 150 gal. of 
water. One died the second, five the third, two the fourth, 
one the fifth and one the seventh day. 

Check experiment : none dead. 

No. 119.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 7 lbs. to 150 gal. 
of water. Five died the third, one the fourth, two the sixth 
and two the seventh day. 

Check experiment : one died the fourth day. 

No. 120.— June 10, 1894. Ten caterpillars, of the 
second molt, were placed on elm leaves which had been 
sprayed with arsenate of lead, in the proportion of 7 lbs. to 
150 gal. of water. One died the fourth, one the fifth, seven 
the sixth and one the ninth day. 

Check experiment : none dead. 

No. 121. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 7 lbs. to 150 gal. 
of water. One died the second, four the third, four the 
sixth and one the seventh day. 

Check experiment : none dead. 

No. 122. —June 28, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 



470 THE GYPSY MOTH. 

with arsenate of lead, in the proportion of 7 lbs. to 150 gal. 
of water. One died the first, one the second, five the fourth 
and three the fifth day. 

Check experiment : two pupated the second and three the 
third day ; two died the fifth day. 

No. 123.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 7 lbs. to 150 gal. 
of water. One pupated the third day ; three died and one 
pupated the fifth day ; one died the seventh, one the eighth, 
two the ninth and one the twelfth day. 

Check experiment : two pupated the fifth day ; one died 
the seventh, ninth and tenth days. 

No. 124. —July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on willow branches which had been 
sprayed with arsenate of lead, in the proportion of 7 lbs. to 
150 gal. of water. One pupated the second day; one died 
the third, one the fifth, one the sixth, one the eighth and 
one the tenth day ; one died and one pupated the eleventh 
day ; one pupated the sixteenth and one the thirty-first day. 

8 lbs. Arsenate of Lead to ISO gal. Water. 

No. 125. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 8 lbs. to 150 gal. 
of water. Three died the second, four the third and three 
the fifth day. 

No. 126. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 8 lbs. to 150 gal. of 
water. Two died the third, three the fourth, four the fifth 
and one the sixth day. 

Check experiment : none dead. 

No. 127.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 8 lbs. to 150 gal. 
of water. Two died the third, two the fourth, two the fifth, 
three the sixth and one the seventh day. 

Check experiment : none dead. 

No. 128.— June 10, 1894. Ten caterpillars, of the 



INSECTICIDES. 471 

second molt, were placed on lettuce leaves which had been 
sprayed with arsenate of lead, in the proportion of 8 lbs. to 
150 gal. of water. Four died the second, two the fourth, 
one the fifth, one the sixth and two the seventh day. 

Check experiment : none dead. 

No. 129. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 8 lbs. to 150 gal. 
of water. One died the second, three the third, one the 
fourth, three the fifth and two the sixth day. 

Check experiment : none dead. 

No. 130. — June 29, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves, which had been sprayed 
with arsenate of lead, in the proportion of 8 lbs. to 150 gal. 
of w T ater. One died the second, three the third, four the 
fourth and two the fifth day. 

Check experiment : four pupated the second, one the third 
and one the fifth day. 

No. 131.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 8 lbs. to 150 gal. 
of water. One pupated the fourth day ; three pupated and 
two died the fifth day ; two pupated the seventh day ; one 
died the ninth and one the twelfth day. 

Check experiment : one pupated the fourth, fifth, seventh 
and ninth days. 

No. 132 (field experiment). —July 9, 1894. Ten cater- 
pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the propor- 
tion of 8 lbs. to 150 gal. of water. One died the third and 
one the fourth day ; one pupated the eighth day ; one died 
the thirteenth day ; three pupated the sixteenth, two the 
twentieth and one the twenty-second day. 

10 lbs. Arsenate of Lead to 150 gal. Water. 

No. 133. — March 7, 1894. Ten caterpillars, three days 
old, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 10 lbs. to 150 gal. 
of water. Five died the second, four the third and one the 
fourth day. 



472 THE GYPSY MOTH. 

No. 134. — May 9, 1894. Ten caterpillars, six days old, 
were placed on lettuce leaves which had been treated with 
arsenate of lead, in the proportion of 10 lbs. to 150 ijal. of 
water. Three died the second, two the third, two the fourth 
and three the fifth day. 

Check experiment : none dead. 

No. 135.— May 28, 1894. Ten caterpillars, of the first 
molt, were placed on lettuce leaves which had been treated 
with arsenate of lead, in the proportion of 10 lbs. to 150 gal. 
of water. One died the third, three the fourth, three the 
fifth, one the sixth and two the seventh day. 

Check experiment : none dead. 

No. 136.— June 10, 1894. Ten caterpillars, of the 
second molt, were placed on lettuce leaves which had been 
sprayed with arsenate of lead, in the proportion of 10 lbs. to 
150 gal. of water. Three died the second, one the third, 
one the fourth, two the fifth, two the sixth and one the 
seventh day. 

Check experiment : none dead. 

No. 137. — June 21, 1894. Ten caterpillars, of the third 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 10 lbs. to 150 gal. 
of water. Three died the fourth, four the sixth and three 
the seventh day. 

Check experiment : none dead. 

No. 138.— June 29, 1894. Ten caterpillars, of the fourth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 10 lbs. to 150 gal. 
of water. One died the second, three the third, five the 
fourth and one the fifth day. 

Check experiment : one pupated the second and one the 
third day ; one pupated and one died the fifth day. 

No. 139.— July 9, 1894. Ten caterpillars, of the fifth 
molt, were placed on elm leaves which had been sprayed 
with arsenate of lead, in the proportion of 10 lbs. to 150 gal. 
of water. Two died and one was lost the fifth day ; four 
died the sixth and three the seventh day. 

Check experiment : one pupated the fourth, two the fifth, 
one the sixth and one the seventh day. 

No. 140 (field experiment). — July 9, 1894. Ten cater- 



INSECTICIDES. 473 

pillars, of the fifth molt, were placed on willow branches 
which had been sprayed with arsenate of lead, in the propor- 
tion of 10 lbs. to 150 gal. of water. Two died the second 
day ; three pupated the fourth day ; two died the fifth and 
one the sixth day ; one pupated the thirteenth and one the 
fifteenth day. 

No. 141 (field experiment) . — June 21, 1893. A branch 
of a small oak tree was sprayed with arsenate of lead, in the 
proportion of 10 lbs. to 150 gal. of water, and eight fifth- 
molt caterpillars placed upon it. August 19, all were dead. 

25 lbs. Arsenate of Lead to 150 gal. Water. 

No. 142. — July 1, 1893. A small branch of oak was 
sprayed with arsenate of lead, in the proportion of 25 lbs. 
to 150 gal. of water, and ten large fifth-molt caterpillars 
placed upon it. All died within one week. Foliage unin- 
jured. 

Even larger proportions of this poison than the above 
were occasionally used in spraying operations in the field, 
with fairly satisfactory results. 

Comparative Effects of Paris Green, Paris Green and Lime 
and Arsenate of Lead. 
A careful study of the comparative effect of equal weights 
of the three substances used in the preceding experiments 
shows that there is practically no choice between Paris green 
and Paris green and lime, so far as the destruction of the cater- 
pillars is concerned. The largest amount of these poisons 
which can be used without injuring the foliage is about 1 lb. 
to 150 gal. of water, and at this, or even a much larger rate, 
the percentage of caterpillars destroyed is not satisfactory. 
Since arsenate of lead in almost any strength is not injurious 
to foliage, a much larger amount can be used than of any of 
the more soluble arsenical compounds ; thus the superiority 
of this poison as an insecticide is at once evident. While 
arsenate of lead may be considered the best insecticide for 
destroying the gypsy moth in the caterpillar stage, even this 
poison is of small value in exterminating this insect, since 
many of the caterpillars survive after feeding upon leaves 
sprayed with large proportions of this poison. 



474 THE GYPSY MOTH. 

The experiments previously recorded show that a consid- 
erable amount of time is required for the poison used to 
affect the caterpillars. Those in the earlier molts were 
killed in a short time, but in the later molts a much smaller 
per cent, was destroyed, many of the caterpillars transform- 
ing and producing imagoes. 

In considering these experiments, it should be remem- 
bered that the insects were in confinement, and obliged to 
eat the poisoned leaves, while in field work they may some- 
times find leaves that have not been sprayed, or that have 
received but little of the poison, and, therefore, the results 
in some cases might be somewhat different from those 
obtained in these experiments. 

The remarkable ability of the gypsy moth to resist the 
action of arsenical poisons is shown in the case of other 
poisons. Mr. Moulton covered a piece of lettuce leaf with 
strychnine, and fed it to a caterpillar. In about an hour the 
caterpillar appeared to be dead, but soon revived and fed 
again for a short time upon the poisoned leaf, when it rolled 
over on its back and for several hours remained apparently 
dead, but afterwards revived again and appeared as well as 
ever. 

Analyses of Poisoned Larvae. 

The remarkable resistance to the action of arsenical 
poisons shown by the gypsy moth led us, in the summer 
of 1894, to institute a series of investigations on the dis- 
position of arsenic by caterpillars when feeding on poisoned 
food. For this purpose, gypsy moth caterpillars which 
had fed for some time upon poisoned leaves without ap- 
parent injury, and also those which had died as a result 
of arsenical poisoning, were carefully dissected, the differ- 
ent organs and tissues being subsequently analyzed at the 
chemical laboratory of Harvard University. The work was 
performed, under my direction, by Messrs. Kirkland and 
Moulton, the former preparing the material and making 
the dissections, the latter conducting the analyses. All the 
operations involved were carried on with extreme care, in 
order to prevent the accidental introduction of any arsenical 
substance. After each dissection the instruments used were 




PLATE 66. Full-grown gypsy moth caterpillars about to pupate on 

the trunk of a walnut tree. From a photograph 

taken in Arlington, July 9, 1891. 



ANALYSES OF POISONED LARViE. 475 

carefully washed in dilute acid and in distilled water, while 
the purity of all chemical reagents employed in the analyti- 
cal work was demonstrated by a number of preliminary 
tests. The method used in testing for the presence of 
arsenic was the so-called Berzelius-Marsh process (Ameri- 
can Chemical Journal, October, 1891), by means of which 
a minute quantity of this poison can be readily recognized. 
The results obtained from analyses of the organs and tissues 
of a large number of caterpillars, which were feeding un- 
harmed on food treated with a liberal amount of Paris green 
or arsenate of lead (the only poisons used) , did not differ 
materially from those of analyses of the same parts of cater- 
pillars which had died from arsenical poisoning, while in 
many caterpillars no arsenic was found. 

In both cases arsenic was found chiefly in the stomach, 
intestinal and rectal contents, and throughout the walls of 
the alimentary canal. It was also found in the excrements, 
in the malpighian vessels, the dorsal vessel and blood and 
in the muscular tissue, thus showing that the arsenic prob- 
ably passes from the alimentary canal, where it is quite 
equally distributed, into the blood, and is carried by the 
circulation throughout the body, and thus eventually per- 
meates all organs and tissues. Owing to the small size of 
the parts subjected to analysis, some of them being of almost 
microscopic dimensions, it was an extremely difficult process 
to determine quantitatively the amount of arsenic present ; 
yet this was accomplished by a comparison of the results 
of the analyses with a series of finely graduated arsenic 
"mirrors," for the use of which we are indebted to the 
courtesy of Professor Hill of Harvard University. 

In some caterpillars, which had fed for a long time upon 
food treated with the arsenical compounds previously men- 
tioned, a considerable amount of arsenic was found ; while 
those w T hich had fed for a shorter time, as a rule, contained 
smaller quantities of the poison. Many of those which had 
thus fed for two or three w r eeks, when killed, were found to 
contain more arsenic than caterpillars which had succumbed 
to arsenical poisoning. One caterpillar, which had fed in 
an out-door cage, upon willow leaves sprayed with arsenate 



476 THE GYPSY MOTH. 

of lead in the proportion of 2 lbs. to 150 gal. of water, from 
July 9 to July 28, 1894, and which at the time of dissection 
was full grown, normally active and healthy, yielded .025 
milligrams of arsenic. If, for the purpose of illustration, 
the weight of arsenic thus found be compared with the 
weight of this caterpillar, and this ratio applied to the aver- 
age weight of the adult human being, we obtain the rather 
surprising result that such a caterpillar would withstand 
uninjured an amount of arsenic, in proportion to its weight, 
equivalent to twelve and one-half times the fatal dose for an 
adult human being, in proportion to the weight of the latter. 
This illustrates the ability of this insect to resist arsenical 
poisoning. 

Since the quantities of arsenic found were small in com- 
parison with the amount the insect consumed, it is evident 
that a considerable part of the poison must have been 
eliminated from the body. The presence of arsenic in the 
excrements of poisoned caterpillars indicates one source of 
elimination. These investigations upon poisoned cater- 
pillars show that an apparently large quantity of arsenic 
may enter and even permeate all parts of the body of the 
caterpillar without interfering with the vital processes, and 
that a considerable part of the poison consumed with the 
food is eliminated, chiefly in the excreta. 

One interesting result obtained from the analyses of the 
different stages of the gypsy moth, made in 1893 and 1894, 
is that pupae and imagoes from caterpillars which have been 
reared on leaves sprayed with Paris green or arsenate of 
lead may contain arsenic in recognizable quantities. Several 
pupae and a few female imagoes, obtained under these con- 
ditions, when subjected to chemical analysis gave ample 
evidence of the presence of arsenic in their bodies. This 
shows that the presence of arsenic in the pupa may not 
materially interfere with the processes involved in the de- 
velopment of the imago. 

Since, as has been repeatedly demonstrated, moths reared 
from poisoned larvae are capable of reproduction, it is also 
evident that the arsenic contained in their systems does not 
injure the reproductive function. 



INSECTICIDES. 477 

Experiments with London Purple and Acetate of 

Lead. 

No. 1. — July 7, 1893. London purple and acetate of 
lead, in the proportion of ^ lb. each to 150 gal. of water, 
were thoroughly mixed and allowed to stand and settle for 
one hour and a half. It was then stirred and allowed to 
stand one-half hour longer, at the end of which time it was 
strained through two thicknesses of cheese cloth, a small 
amount of glucose added, and an oak branch sprayed with 
the mixture. Ten caterpillars, of the fifth molt, were then 
placed upon the branch. July 22, for lack of food, they 
were transferred to a freshly sprayed branch. None of these 
caterpillars died for nearly two weeks after the branch was 
first sprayed, but after they were transferred to the second 
sprayed branch they died more rapidly. Three began pu- 
pating, but none emerged. The foliage of the first branch 
was slightly burned, while that of the second was in good 
condition. 

No. 2. — July 6, 1893. A branch of a small oak tree 
was sprayed with London purple and acetate of lead, in the 
proportion of | lb. each to 150 gal. of water. The London 
purple and acetate of lead were mixed in a little water, glu- 
cose added and thoroughly stirred ; the rest of the water was 
then added and the mixture thoroughly stirred again. Ten 
fifth-molt caterpillars, five very large and five small, were 
then placed on the branch. July 25, the branch was re- 
sprayed, on account of rain. Two of these caterpillars 
began to pupate, but none emerged. They died gradually, 
the last one living nearly a month. Foliage considerably 
burned. 

No. 3. — July 6, 1893. A branch of oak was sprayed 
with London purple and acetate of lead, in the proportion 
of 1 lb. each to 150 gal. of water. The London purple and 
acetate of lead were thoroughly mixed with water in a 
beaker, a teaspoonful of glucose was added and the mixture 
thoroughly stirred. Eleven fifth-molt caterpillars were 
placed on the branch. July 20, the branch was resprayed, 
on account of rain. Of the eleven caterpillars, only two 



478 THE GYPSY MOTH. 

were able to complete the process of pupation and emerge. 
Foliage in good condition. 

No. 4. — July 6, 1893. A branch was sprayed with the 
same mixture and at the same time as in the preceding 
experiment, and ten fourth-molt caterpillars placed upon it. 
Only two of these began to pupate, and both died without 
emerging. Foliage but slightly, if at all, burned. 

No. 5. — July 6, 1893. A branch of a small oak tree 
was sprayed with the same mixture as in the preceding 
experiment, and at about the same time. Ten fifth-molt 
caterpillars, some of which were very large, were placed on 
the branch. July 20, the branch was resprayed, on account 
of rain. Only two of the caterpillars began to pupate, one 
of which emerged. The remainder died on the twenty- 
fourth day after the first spraying. The foliage was slightly 
burned. • 

No. 6. — July 7, 1893. A branch of oak was sprayed 
with 1 lb. of London purple and 2 lbs. acetate of lead to 
150 gal. of water, and ten fifth-molt caterpillars placed upon 
it. Of these ten, only one began to pupate, and this one 
died before completing the process. Foliage only slightly 
burned. 

No. 7. — July 7, 1893. A branch of oak was sprayed 
with London purple and acetate of lead, in the proportion 
of 2 lbs. each to 150 gal. of water. The London purple 
and acetate of lead were thoroughly mixed in a beaker, the 
proper amount of glucose added, and, after being stirred, 
the mixture was poured into the sprayer, the rest of the 
water added and the whole mixed together. Ten fifth-molt 
caterpillars, five large and five small, were then placed on 
the branch. July 20, the branch was resprayed, on account 
of rain. All of the caterpillars except one died before 
beginning to pupate, and this one was not able to complete 
the process. Foliage in good condition. 

No. 8. — July 8, 1893. An oak branch was sprayed 
with London purple and acetate of lead, in the proportion 
of 3 lbs. each to 150 gal. of water. A teaspoonful of glu- 
cose was added, and the mixture thoroughly stirred. Ten 
large fifth-molt caterpillars were placed on the branch. All 



INSECTICIDES. 479 

but one of these died before pupating, and this one did not 
emerge. Foliage slightly burned. 

No. 9. — July 8, 1893. A branch of oak was sprayed 
with the same mixture and at the same time as in the pre- 
ceding experiment, and ten fifth-molt caterpillars placed 
upon it. Only one of these pupated, and that one did not 
emerge. Foliage slightly burned. 

No. 10. — July 8, 1893. A branch was sprayed at the 
same time and in the same manner as in the preceding 
experiment, and ten fifth-molt caterpillars placed upon it. 
July 22, and again on the 25th, the branch was resprayed, 
on account of rain. Six of the ten caterpillars pupated, 
three of which emerged. The foliage was somewhat burned. 

" Antinonnin." 

No. 1. — July 22, 1893. A branch of oak was sprayed 
with antinonnin, in the proportion of 3 lbs. to 150 gal. of 
water, and fifteen caterpillars of the fifth molt placed upon 
it. July 24, the branch was resprayed, on account of rain. 
Six of the caterpillars pupated, four of which emerged. Foli- 
age in good condition. The antinonnin, when sprayed on 
the leaves, presents a bright yellow, glistening appearance, 
and badly stains everything with which it comes in contact. 
It is also easily washed otf by rain. 

No. 2. — July 24, 1893. A branch of oak was sprayed 
with antinonnin, in the proportion of 3 lbs. to 150 gal. of 
water, and ten caterpillars of the fifth molt placed upon it. 
Five of these pupated, three of which finally emerged. Foli- 
age slightly burned. 

No. 3. — July 27, 1893. A branch of oak was sprayed 
with antinonnin, in the proportion of 3 lbs. to 150 gal. of 
water, and fifteen caterpillars of the fifth molt placed upon 
it. Two of these died before beginning to pupate, and ten 
pupated and emerged. Foliage in good condition. 

No. 4. — July 24, 1893. A branch of hop-hornbeam was 
sprayed with antinonnin, in the proportion of 3 lbs. to 150 
gal. of water, and ten fifth-molt caterpillars placed upon it. 
Six of these pupated and finally emerged. Foliage quite 
badly burned. 



480 THE GYPSY MOTH. 

No. 5. — July 27, 1893. A branch of oak was sprayed 
with antinonnin, in the proportion of 3 lbs. to 150 gal. of 
water, and ten fifth-molt caterpillars placed upon it. This 
experiment was started too late to be of any great value as a 
test for the insecticide, as all the caterpillars pupated very 
soon after the branch was sprayed, so that probably few if 
any of them ate enough of the poisoned food to affect them. 

Arsenate of Zinc. 

Prepared in the same manner as arsenate of lead, by sub- 
stituting a soluble zinc salt for the acetate of lead. 

No. 1. — July 11, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 1| lbs. to 150 gal. 
of water, and ten fifth-molt caterpillars placed upon it. 
July 22, and again on the 25th, the branch was resprayed, 
on account of heavy rains. Three of the caterpillars began 
pupating, but none emerged. Foliage badly burned. 

No. 2. — July 11, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 11 lbs. to 150 gal. 
of water, and five large and five small caterpillars placed 
upon it. July 22, the branch was resprayed, on account of 
rain. Six of the caterpillars pupated, four of which emerged ; 
two of these, however, began to pupate before they had time 
to eat much of the poisoned food. Foliage slightly burned. 

No. 3. — July 10, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 2 lbs. to 150 gal. 
of water, and ten large fifth-molt caterpillars placed upon it. 
Six of these began pupating, but none emerged. Foliage 
badly burned. 

No. 4. — July 10, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 3 lbs. to 150 gal. 
of water, and five large and five small caterpillars of the. 
fifth molt placed upon it. July 22, the branch was resprayed, 
on account of rain. Five of the ten caterpillars began pu- 
pating, but none emerged. Foliage badly burned. 

No. 5. — July 10, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 3 lbs. to 150 gal. 
of water, and ten very large fifth-molt caterpillars placed 
upon it. July 20, they were transferred to a freshly sprayed 



INSECTICIDES. 481 

branch, which, July 25, was resprayed on account of rain. 
Five of the ten pupated, one of which emerged. Foliage 
badly burned. 

No. 6. — July 10, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 3 lbs. to 150 
gal. of water, and ten fifth-molt caterpillars placed upon it. 
Five of these began pupating, but none emerged. Foliage 
badly burned. 

No. 7. — July 6, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 6 lbs. to 150 gal. 
of water, and ten lifth-molt caterpillars placed upon it. At 
the end of two weeks all were dead. Foliage burned. 

No. 8. — July 6, 1893. A branch of oak was sprayed 
with arsenate of zinc, in the proportion of 6 lbs. to 150 gal. 
of water, and ten lifth-molt caterpillars placed upon it. All 
but one died within a week, and this one died eleven days 
after the branch was sprayed. Foliage burned. 

Arsenic. 

No. 1. — July 12, 1893. A branch of oak was sprayed 
with arsenic, in the proportion of 6 lbs. to 150 gal. of water, 
and ten caterpillars of the fifth molt placed upon it. July 
19, the branch was resprayed, on account of rain, and again 
on the 25th. Of the ten caterpillars, six began pupating, 
one of which pupated and emerged. Foliage badly burned. 

No. 2. — July 12, 1893. A branch of hop-hornbeam was 
sprayed with arsenic, in the proportion of 6 lbs. to 150 gal. 
of water, and ten caterpillars of the fifth molt placed upon 
it. July 19, the foliage was so badly burned that the cater- 
pillars were transferred to a freshly sprayed branch of oak. 
Only one began pupating, and this one did not emerge. 
Foliage of hop-hornbeam very badly burned, while that of 
the oak was in good condition. 

" Chloro-naptholeum." 
No. 1.— May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf which had been sprayed 
with chloro-naptholeum. At the end of seven days, all the 
caterpillars but one were alive and in good condition. 



482 THE GYPSY MOTH. 

No. 2. — May 15, 1894. Ten caterpillars, before the first 
molt, were placed on a leaf and sprayed with chloro-naptho- 
leurn. One died on the fifth and one on the eighth day ; 
those remaining seemed in good condition. 

No. 3. — May 15, 1894. Ten caterpillars were placed in 
a dish and sprayed with chloro-naptholeum, and then placed 
on a fresh leaf. Fresh leaves for food were given them at 
four different times. One died on the fourth day and one on 
the sixth day ; those remaining were in good condition. 
The strength of the chloro-naptholeum used in this trial was 
in the proportion of 1 lb. to 100 gal. of water. As this 
neither killed the caterpillars nor burned the leaves, it was 
repeated with a stronger solution. 

No. 4. — May 22, 1894. Ten caterpillars, before the first 
molt, were placed on a leaf which had been sprayed with 
chloro-naptholeum. One died on the fifth, two on the sixth, 
two on the seventh, two on the eighth and one on the ninth 
day ; the remaining two were alive and in good condition 
at the end of thirteen days. 

No. 5. — May 22, 1894. Ten caterpillars, before the first 
molt, were placed on a leaf and both sprayed with chloro- 
naptholeum. One died on the fourth, three on the sixth 
and six on the eighth day. 

No. 6. —May 22, 1894. Ten caterpillars, before the first 
molt, were placed in a dish and sprayed with chloro-nap- 
tholeum, and then placed on a fresh leaf. Three died on 
the third, one on the fourth, three on the fifth and three on 
the sixth day. The strength of the chloro-naptholeum used 
in this trial was in the proportion of 1 lb. to 50 gal. of 
water. 

"Electric" Insecticide. 

No. 1. — June 22, 1894. A leaf was sprayed with elec- 
tric insecticide, and ten caterpillars, of the second molt, 
placed upon it. Six died on the second and four on the 
third day. The leaf was badly burned. 

No. 2. — July 22, 1894. Ten second-molt caterpillars 
were placed on a leaf and sprayed with electric insecticide. 
All died on the second day. Leaf badly burned. 

No. 3. — June 2, 1894. Ten caterpillars, of the second 



INSECTICIDES. 483 

molt, were dipped in electric insecticide and then placed on 
a fresh leaf. Nine died on the second and one on the third 
day. The leaf was burned by contact with the caterpillars. 

" Elphona." 

No. 1. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed upon a leaf which had been sprayed 
with Elphona. On the third day all were dead. 

No. 2. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf and sprayed with Elphona. 
Four died on the third, three on the fourth and three on the 
fifth day. 

No. 3. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed in a dish and sprayed with Elphona. 
Nine died on the first and one on the second day. Foliage 
badly burned. 

These three insecticides, " Chloro-naptholeum," "Elec- 
tric" and "Elphona," were sent to the department by their 
manufacturers with the claim that they would kill the gypsy 
moth, but experiments with them proved that when used in 
proportion sufficiently large to destroy the caterpillars they 
burned the foliage very seriously. 

"Hyannis Tobacco Mixture" (a Coxtact Ixsecticide 
with Tobacco as a Basis). 

No. 1. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf which had been sprayed 
with Hyannis tobacco mixture. One died on the fourth 
and one on the sixth day. 

No. 2. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf and both sprayed with 
Hyannis tobacco mixture. One died on the third, three on 
the fifth, one on the sixth and two on the seventh day. 

No. 3. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed in a dish and sprayed with Hyannis 
tobacco mixture. One died on the third, three on the 
fourth and two on the sixth day. The strength of the 
Hyannis tobacco mixture used in this trial was in the pro- 
portion of 1 part to 100 parts of water. 



484 THE GYPSY MOTH. 

No. 4. — May 22, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf which had been sprayed 
with Hyannis tobacco mixture. Three died on the fourth, 
five on the fifth and two on the sixth day. 

No. 5.— May 22, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf and both sprayed with 
Hyannis tobacco mixture. Seven died on the third, two on 
the fourth and one on the sixth day. 

No. 6. — May 22, 1894. Ten caterpillars, before the 
first molt, were placed in a dish and sprayed with Hyannis 
tobacco mixture, and then put on a fresh leaf. Six died on 
the fourth, two on the fifth and two on the seventh day. 
The strength of the mixture used in this trial was in the 
proportion of 1 part to 50 parts of water. 

" SuLPHO-XAPHTHOL.'' 

No. 1. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf which had been sprayed 
with sulpho-naphthol. Two died on the fourth, one on the 
sixth and one on the seventh day. 

No. 2. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf and both sprayed with 
sulpho-naphthol. Two died on the second, one on the 
third, one on the fifth, one on the sixth and one on the 
seventh day. 

No. 3. — May 15, 1894. Ten caterpillars, before the 
first molt, were placed in a dish and sprayed with sulpho- 
naphthol, then placed on a fresh leaf. Three died on the 
second and one on the fourth day. The strength of the 
sulpho-naphthol used in this trial was in the proportion of 
1 part to 100 parts of water. 

No. 4.— May 22, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf which had been sprayed 
with sulpho-naphthol. Three died on the fourth, two on 
the fifth, one on the sixth, three on the seventh and one on 
the ninth day. 

No. 5. — May 22, 1894. Ten caterpillars, before the 
first molt, were placed on a leaf and sprayed with sulpho- 
naphthol. Eight died on the fourth, one on the fifth and 
one on the sixth da v. 



INSECTICIDES. 485 

No. 6. —May 22, 1894. Ten caterpillars, before the 
first molt, were placed in a dish and sprayed with sulpho- 
naphthol, and then put on a fresh leaf. Six died on the 
fourth, one on the fifth, one on the sixth and two on the 
seventh day. The strength of the sulpho-naphthol used in 
this trial was in the proportion of 1 part to 50 parts of 
water. 

Cyanides. 

Studies on the anatomy of the caterpillars, made in 1894, 
by Mr. Kirkland, showed that the contents of the alimentary 
canal were strongly alkaline. This suggested the idea that 
some compound might be prepared which would be inert 
under ordinary circumstances, but when taken into the diges- 
tive system of the insect would decompose in the alkaline 
medium and form a deadly poison. Following out this idea, 
Mr. Moulton prepared a number of the compounds of cyanic 
acid, which were experimented with during the summer of 
1895. The substances tried were the cyanides of lead, 
copper, antimony, zmc and mercury. The last-mentioned 
compound burned the foliage badly, hence but few experi- 
ments were made with it. Of the other compounds, cyanide 
of copper was the only one which gave effective results, and 
these were not as satisfactory as can be obtained from the 
use of the same weight of Paris green. The other cyanides 
are practically valueless, since caterpillars were fed through- 
out their entire life on foliage treated with large proportions 
of these three compounds, without suffering injurious effects. 

Contact Insecticides. 
Whale-oil soap, several proprietary soap powders, soft 
soap and kerosene emulsion were experimented with during 
the summer of 1891, for the purpose of finding a cheap con- 
tact insecticide, for use where the caterpillars cluster in 
masses on trees, fences, etc. All of these insecticides were 
found to be fairly effective. 

Food Selection. 
The following experiments were conducted, both at the 
storehouse and in the field, by Mr. Kirkland, during 



486 THE GYPSY MOTH. 

the summer of 1894, to determine, if possible, whether the 
gypsy moth caterpillars are able in any way to select their 
food, and thus choose the non-poisoned leaves in preference 
to leaves treated with arsenical poisons. For this purpose, 
a definite number of caterpillars were confined upon leaves 
treated with poisons applied in various ways, and the results 
carefully noted for several days, or as long as there was a suf- 
ficient amount of food for them to eat without being forced 
to partake of either the poisoned or non-poisoned leaves. 

Experiment No. 1. — Six elm leaves were selected, and 
a series of bands and dots painted upon each, with Paris 
green, in the proportion of 3 lbs. to 150 gal. of water. 
When the poison was sufficiently dry, so that it did not run 
upon the surface of the leaves, each one was placed in a box 
with three fourth-molt caterpillars. Sixty-five per cent, of 
the feeding was upon the unpainted parts of the leaves and 
thirty-five per cent, upon the painted parts. 

Experiment No. 2. — A series of bands and dots was 
painted upon six willow leaves, with Paris green, in the 
proportion of 3 lbs. to 150 gal. of water. After the poison 
had been applied, each leaf was placed in a box with three 
caterpillars of the fourth molt. These fed about equally 
upon the painted and unpainted parts. 

Experiment No. 3. — Six willow leaves were selected, 
and a number of transverse bands painted upon each with 
Paris green, in the proportion of 3 lbs. to 150 gal. of water. 
The bands were one-fourth of an inch wide, and the un- 
painted space between them one-half of an inch in width. 
Each leaf was then placed in a box with three fourth-molt 
caterpillars. Sixty per cent, of the feeding was upon the 
non-poisoned part of the leaves and forty per cent, upon 
the poisoned parts. 

Experiment No. 4. — A medium-sized twig on an apple 
tree was selected, and from it were removed all the damaged 
and a part of the perfect leaves, so that there were only 
twenty-five leaves left upon the twig. On each of these 
were painted three broad, transverse bands, with Paris 
green and lime in water, in the proportion of 3 lbs. of 
Paris green and 5 lbs. of lime to 150 gal. of water. Ten 



INSECTICIDES. 487 

caterpillars of all sizes below the third molt were then 
placed upon the twig, and sacked in by drawing a bag, 
made of cheese cloth, over it, and tying the open part 
closely around the base of the twig, to prevent the escape 
of the caterpillars. Sixty per cent, of the feeding was upon 
the unpoisoned and forty per cent, upon the poisoned por- 
tion of the leaves. 

Experiment JVb. 5. — Three large willow leaves were 
painted with Paris green, in the proportion of 3 lbs. to 150 
o-al. of water, as follows: on leaf No. 1, three transverse 
bands ; on leaf No. 2, three oblique bands ; on leaf No. 3, 
a band one-fourth of an inch in width around the entire 
margin of the leaf. Each leaf was then placed in a box with 
a full-grown caterpillar. Leaf No. 1 was eaten equally on 
the poisoned and unpoisoned areas ; leaf No. 2 was eaten 
wholly upon the unpoisoned parts ; leaf No. 3 had the mar- 
gin eaten in two places. 

Experiment JVb. 6. — Three willow leaves were prepared 
in the same manner as in the preceding experiment, except 
that, besides the Paris green, 5 lbs. of lime were added to 
the water. Leaf No. 1 had a long, narrow strip eaten from 
the margin, passing through the ends of the three trans- 
verse bands of poison; leaf No. 2 was eaten equally on the 
poisoned and unpoisoned parts ; leaf No. 3 was eaten deeply 
on the margin. 

Experiment JVo. 7. — Three willow leaves were prepared 
as before, using arsenate of lead, in the proportion of 6 lbs. 
to 150 gal. of water, instead of Paris green and lime. Leaf 
No. 1 was eaten equally from the painted and unpainted 
portions ; No. 2 was eaten in the same manner ; and No. 3 
had the margin eaten in two places. 

Experiment JVo. 8. — A small twig of oak, bearing six 
leaves, was sprayed with Paris green, in the proportion of 
10 lbs. to 150 gal. of water, and another twig, bearing the 
same number of leaves, was left unsprayed. Both were 
enclosed in a sack with ten full-grown caterpillars. July 
15. The greater part of the feeding was upon the unsprayed 
leaves. July 16. More was eaten from the unpoisoned 
than the poisoned leaves, yet six of the caterpillars had died. 



488 THE GYPSY MOTH. 

Experiment No. 9. — Two twigs of wild cherry were 
trimmed so that only six leaves remained on each. One of 
these twigs was sprayed with Paris green, in the proportion 
of 3 lbs. to 150 gal. of water, and the other was left un- 
sprayed. Ten full-grown caterpillars were placed upon 
the twigs, which were then enclosed in a sack. July 15. 
None of the leaves were eaten. July 16. Very little was 
eaten from the unpoisoned leaves and a larger amount from 
the poisoned leaves. July 17. The result was the same. 
July 18. Ten times as much had been eaten from the 
poisoned as from the unpoisoned leaves. July 19. Nearly 
all of the leaves upon the poisoned twig had been eaten, 
and but a small portion on the unpoisoned. Three of the 
caterpillars died. 

Experiment No. 10. — A twig of apple, bearing five 
leaves, was thoroughly sprayed with Paris green and lime 
in water, in the proportion of 3 lbs. of Paris green and 5 
lbs. of lime to 150 gal. of water, and a similar twig was left 
unsprayed. Ten full-grown caterpillars were sacked in 
upon the two twigs. The first day the larger part of the 
feeding was upon the poisoned leaves ; on the succeeding 
day nearly all of the poisoned and about half of the un- 
poisoned leaves were eaten. 

Experiment No. 11. — Alternate leaves of a twig of wild 
cherry were painted with Paris green and lime, in the pro- 
portion of 3 lbs. of Paris green and 5 lbs. of lime to 150 gal. 
of water, in such a manner as to cover the entire surface of 
the leaves. Ten fourth-molt caterpillars were then sacked 
in upon the twig. The feeding was nearly equal upon the 
poisoned and unpoisoned leaves. 

Experiment No. 12. — A twig of apple was prepared in 
the same way, using arsenate of lead, in the proportion of 3 
lbs. to 150 gal. of water, and ten fifth-molt caterpillars were 
sacked in upon it. Nearly all of the feeding was upon the 
poisoned leaves. 

Experiment No. 13. — A twig of wild cherry was sprayed 
with arsenate of lead, in the proportion of 6 lbs. to 150 gal. 
of water, and a similar twig on the same branch left 
unsprayed. Ten caterpillars of the fifth molt were sacked 



INSECTICIDES. 489 

in upon the twigs. The amount eaten upon each twig was 
about equal, possibly a little more from the unpoisoned 
than from the poisoned twig. 

Experiment JYo. 14. — A twig of apple was sprayed with 
arsenate of lead, in the proportion of 2 lbs. to 150 gal. of 
water, and a similar twig left unsprayed. These twigs 
were enclosed in a sack containing ten caterpillars of the 
fifth molt. The feeding was about equal upon the poisoned 
and unpoisoned leaves. 

Experiment No. 15. — Alternate leaves on a small twig 
of apple were painted with arsenate of lead, in the propor- 
tion of 6 lbs. to 150 gal. of water, and ten caterpillars of 
the fifth molt were sacked in upon it. The poisoned and 
unpoisoned leaves were eaten equally. 

Summary. 

Of the four experiments where the caterpillars ate more 
of the poisoned than of the unpoisoned leaves, Nos. 9 and 
10 give most decided results against the choice of unpoi- 
soned food. Of the four cases where the caterpillars ate 
more from the unpoisoned than from the poisoned food, 
Nos. 1, 3 and 4 give but a small margin upon which to base 
a conclusion. The fourth, No. 8, is of somewhat doubtful 
value, because six of the caterpillars died upon the second 
day of the experiment. Balancing experiments Nos. 1, 3, 
4 and 8 against Nos. 6, 9, 10 and 12, there remain seven 
experiments where there was no apparent choice of food. 

A fair conclusion from these results is that there was 
no discrimination against foliage treated with the poisons 
employed. 

Effect of Insecticides on Foliage. 

No. 1.— June 26, 1893. A mixture of f lb. of Paris 
green, £ lb. of lime and 2 quarts of glucose to 150 gal. of 
water was applied to some quince bushes. About one- 
fourth of the leaf surface was destroyed by burning. 

No. 2. — July 12, 1893. A branch of apple tree was 
sprayed with Paris green and lime, in the proportion of 1 



490 THE GYPSY MOTH. 

lb. of each to 150 gal. of water. The branch was sprayed 
twice, on account of rain. The foliage was very badly 
burned. 

No. 3. — July 12, 1893. A branch of apple tree was 
sprayed with the same mixture, and by July 30 the foliage 
was very badly burned. 

No. 4. — July 12, 1893. In order to get as near as 
possible the exact effects of lime on the foliage, the two fol- 
lowing experiments were used as checks on those preceding. 
They were sprayed within an hour of each other, and all 
conditions were as nearly the same as it was possible to 
have them. In this experiment a branch of hop-hornbeam 
was used as a check to No. 1. The branch was resprayed, 
on account of rain. July 30, the foliage was burned worse 
than that of experiment No. 1, even though the branch in 
the latter had been sprayed three times. 

No. 5. — July 12, 1893. An apple-tree branch was used 
as a check to experiment No. 2. The branch was resprayed, 
on account of rain, and August 6 the foliage, though some- 
what burned, was not as much so as in experiment No. 2. 

No. 6. — July 12, 1893. An apple-tree branch was 
sprayed with Paris green, in the proportion of 1 lb. to 150 
gal. of water, the mixture having been allowed to stand for 
nearly three hours. August 6 the foliage was very badly 
burned. 

No. 7. — July 13, 1893. A branch of hop-hornbeam was 
sprayed with Paris green and lime, in the proportion of 1 
lb. each to 100 gal. of water. The branch was resprayed 
twice, on account of rain. July 27, the foliage was very 
badly burned. 

No. 8. — July 12, 1893. A branch of apple tree was 
sprayed with arsenic, in the proportion of 1 lb. to 25 gal. 
of water. July 19, the branch was resprayed, on account 
of rain, and again on the 25th. August 6, the foliage was 
badly burned. 

No. 9. — July 20, 1893. A branch of apple tree was 
sprayed with arsenate of zinc, in the proportion of 1 lb. to 
50 gal. of water. August 6, the foliage was badly burned. 

No. 10. — July 1, 1893. A small hop-hornbeam branch 



INSECTICIDES. 491 

was immersed in a solution of 2 lbs. of arsenate of lead 
mixture, making 1 lb. of precipitate to 150 gal. of water. 
Foliage uninjured. 

No. 11. — July 1, 1893. This experiment was similar to 
the one preceding, except that the branch was sprayed, in- 
stead of being immersed. A branch of a small oak tree was 
sprayed with arsenate of lead mixture, in the proportion of 
2 lbs. to 150 gal. of water. Foliage uninjured. 

The "burning" effect of Paris green, when used in any 
proportion greater than 1 lb. to 150 gal. of water, has been 
ascribed to the presence of a small quantity of soluble 
arsenic contained in the poison. Many chemists and ento- 
mologists have recommended the addition of lime to the 
mixture of Paris green and water used in spraying, in order 
to neutralize this soluble arsenic. Our experiments, how- 
ever, have tended to prove that the addition of lime is of 
questionable value. 

In some cases we have used a considerable strength of 
Paris green and lime without burning the foliage, while in 
other cases a marked burning has resulted. The same vari- 
ation in burning effects is often noticed where Paris green 
is used alone. We are led to believe that the burning 
caused by the use of Paris green and lime is dependent in a 
great measure upon the amount of lime added, and also 
upon the length of time the mixture is allowed to stand, 
as our experiments have shown that, where a consider- 
able quantity of lime is added to the Paris green mixture 
and allowed to stand for some time, there is far greater 
danger of burning the foliage than there would be from the 
use of Paris green alone, thus apparently indicating that 
the lime decomposes the Paris green in part, and forms a 
more soluble compound of arsenic. 

At my request, Dr. Charles Wellington, professor of 
chemistry at the Massachusetts Agricultural College, has 
made a series of analyses of Paris green mixed with water 
and of Paris green and lime mixed with water, with a view 
of determining whether the lime would decompose the 
arsenite of copper contained in the Paris green, and in- 
crease the per cent, of soluble arsenic in the mixture. An 



492 



THE GYPSY MOTH. 



extract from his report on the result of these investigations 
is snven below : — 

o 

Paris green, a preparation of arsenite of copper, is insoluble in 
water, but yields to it a small amount of arsenious oxide, with a 
mere trace of copper. 

The Paris green employed in these examinations was a mixture 
of several samples, all obtained from the Hampden Paint and 
Chemical Company of Springfield, Mass. 

Its composition was as follows : — 

Per Cent. 

Water, 1.20 

Copper oxide, 30.46 

Arsenious oxide, 59 . 94 

Insoluble, .12 

Other material and difference, . . . . 8.28 

Total, 100.00 



After allowing mixtures of Paris green and water to stand with 
occasional agitation, I have found the following amounts of arse- 
nious oxide in solution : — 



Taken'. 


Time 

of Standing 
(Hours). 


Found Arsenious 


Paris Green 
(rounds). 


Lime (Pounds). 


Water 
(Gallons). 


Oxide (Grains 
per Gallon). 


a, 




1 


None. 


150 


3 


0.33 


6, 


. 


1 


None. 


100 


3 


0.46 


c, 


• 


1 


None. 


125 


i 

5 


0.11 



The free arsenious acid would appear to be the cause of the 
damage to the foliage. 

Alkaline substances generally neutralize arsenious acid, forming 
with it salts known as arsenites. Lime, soda and potash are 
materials which thus act. Any one of these could be added to 
the mixture in such proportion as to exactly neutralize all free 
acid. 

These substances, however, are sufficiently powerful as bases to 
withdraw the arsenious acid from the copper. This is accom- 
plished either partially or wholly, according to the favoring cir- 



ANALYSES OF PAEIS GREEN. 



493 



cuHistances of concentration and heat. In moderately concentrated 
solutions of soda or potash {i.e., sodium hydrate or potassium 
hydrate) all the copper is removed from Paris green as insoluble 
cuprous oxide. Soluble soda or potassa arsenite is then formed. 

In such dilute solutions as are here considered, this could not 
occur, and yet considerable portions of the arsenious acid may be 
removed from the copper compound. To show this, I have made 
the following determinations with the use of lime. In each case the 
Paris green and lime were mixed, placed in the water, the mixture 
agitated occasionally and at the end of the designated time fil- 
tered : — 



Taken. 


Time 

of Standing 

(Hours). 


Found Arsenious 


Paris Green 
(Pounds). 


Water 
Lime (Pounds). (GaJJons) . 


Oxide (Grains 
Per Gallon). 


d, . . 1 

e, . . 1 
/. . . 1 

g, ■ . i 


5 
5 
5 
5 


50 
100 
125 
150 


3 
3 
3 
3 


0.77 
0.92 
1.09 
1.33 



By substituting for this very large amount of lime smaller quan- 
tities, proportionally smaller quantities of arsenious oxide were 
dissolved. 

To illustrate the relative solvent effect in different periods of 
time, the following determinations serve : — 



Taken. 


Time 

of Standing 

(Hours). 


Found Arsenious 


Paris Green 
(Pounds). 


Lime (Pounds). 


Water 
(Gallons). 


Oxide (Grains 
Per Gallon). 


h, . . 1 
•', . . 1 

j, • • 1 
k, . . 1 


5 
5 
5 
5 


125 
150 
125 
125 


1 
4 
X 
4 
3 
10 


0.69 
0.74 

1.09 
1.23 



Trials with the use of soda gave the following results : — 



Taken. 


Time 

of Standing 

(Hours). 


Found Arsenious 


Paris Green 
(Pounds). 


Soda (Pounds). 


Water 
(Gallons). 


Oxide (Grains 
Per Gallon). 


1, . . 1 

m, . . 1 


| 125 
1 125 


1 
4 
1 
t 


0.17 

0.31 



494 



THE GYPSY MOTH. 



The lime is understood to be quicklime, the soda to be crystal- 
lized neutral soda carbonate. 

It is thus seeu that either with the use of lime or of soda a 
certain quantity of arsenious oxide is removed from Paris green 
beyond that which water alone would remove. The actual amount 
removed depends upon the proportions of the substances mixed, 
as well as the time allowed for solution. In every case this amount 
is in the form either of lime or soda arsenite, and is in solution. 

The " burning;" of foliage which occurs as the result of 
spraying with arsenical poisons is due to the presence of 
soluble arsenic, which is found to some extent in Paris 
green and to a greater degree in London purple. Other 
poisons which contain arsenic in a practically insoluble 
form, as, for instance, arsenate of zinc, when sprayed on 
the foliage and fully exposed to atmospheric influences as 
well as to the physiological action exerted by the leaves 
themselves, sometimes decompose to a certain extent, and 
give rise to soluble compounds of arsenic. The effect of 
soluble arsenic on leaves is to kill the protoplasmic contents 
of the cells which compose the living or assimilative part 
of the leaf, as is shown by the illustrations given below : — 





Fig. 1. Section through normal leaf of 
pig-nut hickory ( Carya porcina) , show- 
ing structural elements. E, epidermis; 
PC, palisade cells; SP, spongy paren- 
chyma; S, stoma or breathing pore. 
{After KirJcland.) 



Fig. 2. Section through leaf of same 
tree, " burned " by excess of Paris 
green. Cell contents {protoplasm) of 
palisade cells and spongy parenchyma 
dead and dried up ; cell walls shrivelled. 
{After KirJcland.) 



Leaf Area of Trees. 
To gain a better knowledge of the surface which needs to 
be covered in spraying operations, during the summer of 



LEAF AREA OF TREES. 495 

1895 studies were made, under my direction, by Messrs. 
Kirkland and Hylan, upon the leaf area of three average- 
sized trees, as follows : — 

The dimensions of a medium-sized Baldwin apple tree 
were carefully measured and the leaves upon one-fourth of 
the tree counted. The average area of a single leaf was 
computed by careful measurement of ten average leaves, 
and the total leaf area ascertained by multiplying the whole 
number of leaves by this last factor. The data concerning 
the tree are given below : — 

Height of tree, 23 feet. 
Diameter of top, 23 feet, 9 inches. 
Diameter of trunk, 1 foot, 5£ inches. 
Number of leaves, 99,040. 

Average area of single leaf, 30.188 square centimeters. 
Leaf area of tree, 298.981952 square meters or 3,218.25 square 
feet. 

A second Baldwin apple tree afforded data as follows : — 

Height, 18 feet, 5 inches. 
Diameter of top, 26 feet, 7 inches. 
Diameter of trunk, 1 foot, 5£ inches. 
Number of leaves, 108,540. 

Average area of single leaf, 29.294 square centimeters. 
Leaf area of tree, 317.957076 square meters or 3,422.49 square 
feet. 

The leaf area of a red oak ( Quercus rubra') was computed 
with the following result : — 

Height of tree, 41 feet, 6 inches. 

Diameter of top, 37 feet. 

Diameter of trunk, 1 foot, 3 inches. 

Number of leaves, 35,764. 

Average area of single leaf, 83.5705 square centimeters. 

Leaf area of tree, 298.88 square meters or 3,217.16 square feet. 

In the actual spraying of trees the poison mixture should 
be thoroughly applied to both surfaces of the leaf; so that, 
to find the amount of surface necessary to be covered in 
spraying these trees, the area should be doubled. 



APPENDICES. 



Appendix A 



REPORT OF A CONFERENCE HELD AT THE ROOMS OF THE 
STATE BOARD OF AGRICULTURE, BOSTON, MASS. 

Mabch 4, 1891. 

Present : Profs. C. V. Riley and C. H. Fernald, Mr. Samuel 
Scudder of Cambridge, Mayor Wiggin of Maiden, Selectmen 
L. S. Gould of Melrose, W. C. Craig of Medford, and W. A. 
Pierce of Arlington, Messrs. Shaler, Appleton and Sessions of 
the Gypsy Moth Commission, and others. 

Professor Shaler. You know that about twenty years ago an 
interesting Frenchman brought an interesting bug to this country. 
His name was Trouvelot, and he brought the creature thinking to 
introduce it as a valuable silk-worm. I begged him to destroy 
his specimens, and at one time he said he had. It appears, how- 
ever, that they got away from him. Last year I went before the 
Legislature and begged for some money, advising them to put a hun- 
dred thousand dollars at the disposition of a trustworthy commission. 
They appropriated fifty thousand dollars and appointed a commission 
which did a good deal of work and expended a good deal of money 
and energy. I begged them to bend their energies to bringing in the 
boundaries as far as possible, to pay the market price for eggs and 
grubs, and to put their inspection work in progress ; but they went 
into a miscellaneous sprinkling and burning over the whole terri- 
tory. The result now is that, as nearly as I can ascertain, it 
would take a line thirty miles long to enclose the area these insects 
occupy. They are found in a territory of not far from fifty square 
miles, though not all over it. I should think that not more than 
ten square miles were solidly occupied. On the rest of it there 
are colonies here and there. The situation seems to me discour- 
aging in a certain way, but it is an encouraging fact that in about 
twenty years they have not occupied more than about fifty square 
miles, and it shows that they are not to be readily transported to a 
great distance. Another encouraging fact is that, as far as I can 
learn, save at two or three very limited points south of the Charles 
River, the creature may be enclosed in this line on this side the 



iv THE GYPSY MOTH. 

river [a map was shown], which it does not seem to have passed 
easily. It passed these few points probably in hauling manure. 

Professor Fernald. Are you quite sure of the boundaries? 
They are reported in Maine and Western Massachusetts. 

Professor Shaler. I know they are, but putting the worst face 
upon it, as I am at present doing, I think an area of something 
like five by ten miles is the region that has got to be closely 
studied. There is a reasonable suspicion of it over an area of say 
fifty square miles, and the work has got to be done over that area. 
One of the discouraging features is that there is a great traffic 
through this territory. Railroads and wagon roads go through it, 
and there is a large traffic in manure out of the district. We have 
twenty-four thousand dollars to spend for certain, and I am sure 
the Legislature will give us anything in reason we ask for. 

Mr. Appleton. It seems to me the situation is this : Can we 
eradicate this thing, and, if so, how? If we cannot eradicate it 
entirely, what is the best we can do? Now, the first question to 
consider, it seems to me, is, Can we eradicate it, or not? 

Professor Shaler. We should like to have the opinion of ex- 
perts on that point. Professor Riley, will you give us your word ? 

Professor Riley. I will be very glad to give you whatever 
suggestions I can on the subject. I have taken the same interest 
in this matter since it was so prominently announced that I do in 
all matters of applied entomology, and I have felt that in the niaiu 
Professor Fernald's original suggestions were very wise. The in- 
sect, as Professor Shaler has well said, has but limited powers of 
spreading. While the female has wings, it is heavy bodied and 
flies but little, and the history of the past twenty years shows that 
its spread has been very gradual. Therefore we have a condition 
of affairs totally different from that prevailing in the insect's native 
home, Europe, and we are justified in making a strong effort to 
undo the harm that has been done. That brings up, first of all, 
the question : Is it practicable to exterminate it, or not ? In view 
of Professor Shaler's statement, I have serious doubts, because, if 
it may be said to occur in an area of say fifty square miles, if it is 
found even in a number of central points of distribution in that 
area, there is great danger, in my judgment. My own fears would 
be that it has got into the woods and on to trees that are not so 
easily treated. So long as it was confined to cultivated trees and 
plants under cultivation I think there would have been no difficulty 
at all, and the authorities would have been blameworthy in allow- 
ing it to go out from Massachusetts over the rest of the country. 

Professor Shaler. I don't think it has gotten into the woods. 
I think it is still confined to the artificial grounds, as yet. 



APPENDIX. v 

Mr. Appleton. Don't you think it would be a good plan to 
ask these gentlemen representing the different towns what their 
experience is in that direction? 

Mr. Craig thought, in a general way, that they did not attack 
forest trees ; were confined, as a rule, to orchard trees and trees 
surrounding houses. Thought the reason the spread was not 
greater the last twenty years was because the people took the in- 
sect for some kind of canker-worm, and took pains to burn them 
off the trees, which they did until they became too numerous to 
control. He recommended the use of tarred paper tied round the 
trees with a string. Undoubtedly the commissioners had destroyed 
a great many of the insects. 

Professor Riley. It is well known to feed upon a number of 
different forest trees that grow with us, and in the event of its 
getting beyond cultivated plants I should, as I said, have very 
little hope of its ultimate extermination. I am not an alarmist, 
and I do not believe that our people need be so very seriously 
affected if it is not exterminated ; but, aside from that, the loss 
would go on increasing annually, and it would become a very 
grievous additional pest to those the farmer and fruit grower 
already have to contend with. The thing you have to consider is 
this : from what I could gather from the accounts in the news- 
papers, three measures were adopted : first, by attempting to 
destroy the eggs ; secondly, by attempting to destroy the cater- 
pillars after they had hatched by means of arsenical spraying ; 
thirdly, by endeavoring to stop the artificial spread of the pest on 
vehicles, manure wagons, etc. 

Individually I have always felt, and so expressed myself, and 
still feel, that the proper way would be to use whatever funds the 
State will give you during a limited time, and concentrate all effort 
and all expenditure in the month of June on the destruction of 
caterpillars, and not to bother about the destruction of the eggs or 
the prevention of the spread of the insect. These latter methods, 
necessarily intrusted to persons who may be efficient or who may 
not, are apt to bring the whole subject into popular disrepute and 
disfavor. You may reduce the numbers, but you will never exter- 
minate it by destroying the eggs. Therefore, as a single spraying 
of a tree will kill five thousand caterpillars just as well as one, 
there is nothing to be gained by the work of destroying the eggs. 
Moreover, I do not believe there is much to be gained in the work 
of preventing its spread by the examination of vehicles on the 
main thoroughfares and on the railroads. On the contrary, I 
believe that the only way to accomplish that end is by a very strict 
law which the Legislature should pass, giving the power to some 



vi THE GYPSY MOTH. 

committee to absolutely prohibit the sending of nursery stock or 
any plant growth or material, probably including manure, out of 
an infected district without inspection. My belief is that a rigid 
quarantine law, making it a penal offence for a nurseryman to 
send cuttings or trees from any given infected area, without first 
having the sanction of this commission, would be effective in pre- 
venting the spread. That is to say, there should be a competent 
person or persons appointed, to whom all such shipments should 
be submitted, and only upon their approval should such shipments 
be allowed to pass out from that area. That would be the only 
simple and efficient way of preventing its spread. My impression 
is that the danger is far greater from overlooking a batch of eggs 
during the months of the year when such a thing is possible, and 
of the insects being transmitted in that way, than there would be 
in the mere carrying of the caterpillars. I would therefore con- 
centrate all effort on the destruction of the caterpillars. 

I believe that even in an area as extended as Professor Shaler 
indicates, if the Legislature would appropriate a hundred thousand 
dollars the thing could be done. Let it be used under the intelli- 
gent guidance of some one who has had experience, who knows 
practically how to spray, who can go to work intelligently and 
instruct his men, and have a sufficient force to examine every tree 
and cultivated plant upon which this insect is known to feed, and 
make sure that wherever it is it will be destroyed before the change 
into the chrysalis state takes place. In other words, I do not see 
why, with one hundred thousand dollars, a single year ought not 
to suffice to stamp it out from the area in which you know it to be 
found. I believe it can be done, and that the State of Massachu- 
setts would be justified in making the attempt. 

In Europe this injury is at times not great, at other times it is 
quite extensive; but it is chiefly notable in those places where 
there are very large areas of cultivated forests. Bavaria, for 
instance, has lately suffered greatly from it. Experience there 
has shown that it is easily checked by the use of sticky bands, 
very much the same methods as you have employed here for the 
canker-worm. They use several kinds of glue (manufactured and 
some of them patented by different firms) , which is procured in 
large quantities and smeared on the trees, being made in such a 
way that it does not dry. I presume it comes nearest to our 
printers' roller glue. The caterpillars never pass above it from 
below. Coming down the tree they jump over it. The devices 
for putting it on are very simple. That is the method which ex- 
perience has shown to be the most satisfactory there, but it is a 
preventive method, and chiefly to be considered when you have 



APPENDIX. vii 

given up the fight for extermination. The main thing for you to 
do is to try to stamp it out during the active season and use all 
your energies to that end. The arsenicals are not expensive, and 
if an analysis is made of the Paris green, or whatever form of 
arsenic is used, to insure its purity, I can see no reason why the 
whole area should not be practically cleared off during a single 
season. That should be carefully followed up by close observa- 
tion, with a view of repeating it in the case of some omitted centre 
or point where they may be found in a subsequent year. In case 
they have not gone into the woods, it seems to me feasible to ex- 
terminate them. 

I would make one other suggestion, and that is, that as an 
auxiliary method it would be well to spend five hundred or six 
hundred dollars in sending one or two persons abroad next sum- 
mer with no other object than to go to some section of northern 
Europe to collect and transmit to authorized persons here a certain 
number of the primary parasites of this species, which are known 
to check its ravages over there. The insect was undoubtedly 
brought over by Trouvelot without any of its natural checks. In 
my judgment it would be well worth trying to import its parasites 
from abroad. The advantage would be this : if you failed to 
exterminate it by spraying, its parasites, seeking for this partic- 
ular host, would be more apt to find the overlooked or escaped 
specimens than man would. 

Professor Fernald. Do you think that any of our native par- 
asites will be liable to attack this insect? 

Professor Riley. Experience justifies the belief that some of 
them may, in time. 

Professor Fernald. Have we a case on record? 

Professor Riley. Yes, though they are not numerous. Pieris 
rapce, or the imported cabbage- worm, has some native parasites. 
There are other cases, but I should have to consult my notes. 

[Note by Professor Riley. Several native species attack Scoly- 
tus rugulosus : the same is true of the hop aphid, Phorodon humuli, 
and of several important species of bark lice.] 

Professor Fernald. In reply to the question which was first 
asked, as to whether it is possible to eradicate the insect at all, 
let me suppose a case. Suppose we have a tree like the elm I see 
yonder, and suppose we know it to be the only tree in America 
that is infested. I think you will all agree with me that for a small 
sum of money all moths on it could be destroyed. Suppose there 
were two, — suppose all the trees on the Common were infested. 
If they could be destroyed on all those trees, it is only a ques- 
tion of time and money to eradicate them from a much larger 



viii THE GYPSY MOTH. 

territory. It is a question of time and intelligent labor. I say- 
intelligent advisedly. Right here I would suggest very earnestly 
that the committee or commission employ a scientific man upon it. 
This is the advice I gave, with all the force I could, to the former 
commission, for there are a thousand and one things constantly 
coming up in work of this kind, and it is necessary to have some 
one who knows and is able to answer questions. As to the ques- 
tion of territory, I only raised that to know how it had been 
determined. It is possible it is not so extensive as indicated, but 
it may be. 

Professor Shaler. I thought it best to put it at the highest 
figure. My own opinion is that we shall not have to deal with an 
actual area of more than nine or ten square miles. 

Professor Riley. Is it not true that so far you have found this 
pest chiefly on orchard trees ? 

Professor Shaler. On orchard trees and elms. 

Professor Riley. That is unfortunate, because it increases the 
difficulty of treatment. 

Mr. Craig. They are more numerous on and generally select 
orchard trees, but even pine trees have been attacked by them 
and in some cases the branches stripped. Maple trees are also 
attacked. 

Professor Shaler. I have seen them on some maple trees and 
heard of others, but it seems to be a case of starvation when they 
come to that. 

Mr. Craig. My observation is that the older the tree the more 
they will attack it. 

Professor Fernald. With regard to a scientific man on the 
commission, if you can get an entomologist who is also a business 
man you will be fortunate, but in my judgment it is important to 
have a business man too. 

To go back to the question of territory, I agree with Professor 
Riley that it is rather stupendous ; but if } t ou can destroy the 
insects over a small area, why cannot you over a large one? The 
whole thing is experimental ; it is unprecedented to destroy so 
many insects scattered over so large a territory, but my impres- 
sion is that they can be destroyed. The question is, how to do it. 
I was informed last summer that Paris green destroyed the larvse 
of this insect up to a certain size ; beyond that size they were able 
to eat it and grow fat. I urged the commission to try a branch 
with caterpillars that had not eaten any Paris green, but I cannot 
learn that they did it. If their statements are correct, I must lose 
the little faith I had in regard to the efficacy of Paris green. My 
experiments at Amherst on the use of Paris green do not seem to 



APPENDIX. ix 

tally with the results they obtained. They used one pound of 
Paris green to one hundred and fifty gallons of water, and when 
Mr. Sessions and I went over there in the summer we saw that the 
trees were burned very little. The same proportions used at 
Amherst burned the trees very badly. Yet Professor Cook and 
others have reported that a much larger proportion of Paris green 
could be used. The Paris green I used I had analyzed and know 
just what it was. I expect there is either some great difference 
between the climate of Amherst and this region — or something 
else. 

Mr. Craig. So far as my own orchard is concerned, where the 
Paris green was used a streak was burned here and there, in other 
places not. I think it was not kept stirred up. 

Professor Fernald. Suppose it is not possible to destroy these 
insects : even then I believe it would pay to make annual appro- 
priations to hold them in check. We know what the farmers are 
paying annually to destroy the potato beetle, and if this insect 
spreads over the Commonwealth of Massachusetts I should sup- 
pose it was capable of doing more damage than the potato beetle. 
It seems to me, if it is not possible to stamp it out, it is wise to 
hold it in check where it is. 

Mr. Sessions. I have heard the idea advanced by somebody 
from Medford that possibly the reason the caterpillars apparently 
eat Paris green and live is that after a certain stage of their 
existence they stop eating altogether. 

Professor Fernald. They do not stop eating long before they 
spin their cocoons. The time is not more than twenty-four hours. 

Professor Shaler. I should like to ask about the chances for 
more satisfactory insecticides. I should like to ask if we may 
reckon among the insecticides certain compound salts of calcium 
which are very acrid, and whether a solution of them would be 
efficacious? 

Professor Fernald. I have had no experience with them. 

Professor Shaler. The question is, whether it would serve in 
this case. Do you know, Professor Riley ? 

Professor Riley. I should have most faith in the arsenicals. 
The relative value of the different forms of arsenic spraying depends 
partly upon the kind of tree treated, partly upon the condition 
of the atmosphere, and very materially upon the purity of the ma- 
terial. Paris green has this advantage, that it may be used much 
more strongly with less injury to the trees ; and it has this disad- 
vantage, as compared with London purple or pure arsenic, that it 
is not soluble in water, and you have to keep stirring it. I have 
no doubt that the experience Professor Fernald referred to was 



x THE GYPSY MOTH. 

due to the inferior character of the Paris green in the one case 
and its purity in the other. It should be applied with a spraying 
nozzle that would simply touch it to the leaves, and it should be 
mixed with a substance to make it adhere. In other words, al] 
this work should be superintended by a careful, practical man, 
who knows what to do. A part of the advantage of using the 
arsenicals in this part of the country would be that, aside from the 
destruction of Ocneria, it would pay to use it as against the tent 
caterpillar, the codling moth and various other insects that are so 
prevalent in your orchards. It is one of the curious things which 
strike a man travelling through Massachusetts that in a State 
where applied entomology has had its origin in America, an insect 
as common as the tent caterpillar, and which may be so easily mis- 
taken for this very Ocneria, should be so abundant, and that so 
little should be done to control it. You will have the same 
trouble with the Ocneria. You can't get the average Massachu- 
setts farmer to bestir himself about it. 

Professor Shaler. Am I not right in supposing that our first 
care should be to drive this pest in on the periphery at all costs, 
but to make surest of its destruction on the periphery ? The num- 
ber of inspectors we could have would be limited, therefore we 
should take the extremest care with the periphery. With that in 
view, how would it do, from now until the time the eggs hatch 
(they are conspicuous things, — you can see them a great distance, 
and boys could gather them in quantities), to pay the school-boys 
what would be a tempting price per ounce for the eggs? We 
would secure a very large destruction on that basis, I think, be- 
tween now and the time the eggs hatch. We could put a person 
in each town who should gather the eggs once a day, pay for and 
destroy them, — that is, in the regions that are thoroughly in- 
fected. In that way I think we should diminish the number that 
are to be killed in the spring, and that at small cost. 

Professor Ferxald. In reply to that, Professor Eiley has 
already expressed his opinion. A year ago I had just the same 
opinion that Professor Riley has, and expressed it to the commis- 
sioners, but they had already gone to work. I talked with some 
entomologists about it, and they differed from me ; they thought 
it was beneficial to use other means than Paris green. Theoreti- 
cally it seems to me that any other means would be a needless 
expenditure of money, and Professor Riley's suggestion to exter- 
minate them in one year would be a good one if it could be accom- 
plished ; but I question whether it would be wise for us to go 
from this meeting to the Legislature with that proposition. If 
you failed to do it in one year and came back for a second appro- 



APPENDIX. xi 

priation, you might find it difficult to get it. This is merely a 
policy suggestion. I can conceive that, even with the most thor- 
ough work that can be done with Paris green in spraying trees, a 
few might escape and start a new colony. Then in another twenty 
years this thing would come up again. 

Professor Shaler. Do you gentlemen agree that we must look 
forward to a careful and continuous work against this moth ? 

Professor Rilet. As I said before, we have nothing to do 
with the experience or methods of Europe, where the insect pre- 
vails over vast areas, and where nobody expects to exterminate 
it. Yet there have been instances of similar extermination, as, 
for instance, what the Prussian government did with the potato 
beetle; and here you. have an opportunity to show that you can 
stamp this thing out. I expect a few will escape. That is why 
I made the suggestion that it would be wise to introduce such par- 
asites as can be used against it, with a view of permitting them 
to search out those which may have escaped. The matter, as I 
said, may not be possible ; but, if it is, it is only possible in that 
way, and all other efforts would, I think, be rather puerile, and 
serve to bring the whole thing into popular disfavor. Set the 
school-boys to work on the eggs ; that is good as a prophylactic 
measure, and would do a certain amount of good, but the good 
would be very slight as compared with the effective work you 
ought to do in the actual destruction of the caterpillars. As I 
said before, the fact that the insect has been diminished in num- 
bers would be rather against the efficient extermination of the 
larvae in summer, for the reason that it is harder to find an isolated 
bunch of caterpillars in a county than when they are numerous. 
I still hold to the belief that whatever funds the Legislature can 
give you should be devoted to a prompt and effective attempt 
at stamping out. 

Professor Shaler. Suppose every tree sprayed, what reason 
have we to believe that we should have disposed of the pest? 

Professor Riley. There would be need for some years after- 
ward of the greatest care. I would not attempt to kill the young 
caterpillars ; wait until they are somewhat advanced, so that the 
work could be concentrated within a narrow limit of time. 

[At this point Mr. Scudder came in.] 

Professor Shaler. The discussion has been, Mr. Scudder, on 
the question as to whether it would be well to proceed at once to 
the destruction of the eggs. There are places where the eggs are 
abundant, and, as we know, they are conspicuous, and it seems 
that between now and hatching time we might collect a consider- 
able per cent, of them, paying for them by weight or measure, 



xii THE GYPSY MOTH. 

and at once destroying them. Professor Riley thinks that would 
diminish the conspicuousness of the colonies, so to speak, and 
make it harder to find them, and thinks that an equal amount of 
money would go further in poisoning with spray than it would in 
collecting the eggs. I should like to hear from Mr. Scudder 
what he thinks about the desirableness of doing anything with the 
eggs. 

Mr. Scudder. I feel that I have no right to speak in the 
presence of others here who have given special study to economic 
entomology, while I have not. All I can speak upon is the 
natural history of the moth, and on that side of the question it 
might be well to ask whether it is behaving the same in this 
country as in the old country. There are a number of moths 
single-brooded in the old country which are double-brooded here. 

Professor Riley. I have assumed that it was single-brooded. 

Professor Fernald. I have bred it twice, two years in succes- 
sion. 

Mr. Scudder. If it is single-brooded, there is this point to be 
brought out, that, as the caterpillar is a very liberal feeder, so, of 
course, it is very much more difficult to reach by spraying, because 
the spraying is not to be confined to a few kinds of trees, but to a 
very large number, so that one would say you would have to spray 
almost everything you came across. So with the eggs, which are 
laid not always on trees, but on almost anything else. It there- 
fore becomes the most dangerous insect enemy we have had for a 
long time, I think. If it is single-brooded, it seems to me that 
nature has indicated the easiest means of attack. The eggs are 
laid in batches, and are exposed for eight months of the year. 
Therefore it seems to me that the egg is the place to attack. I 
should suppose that the same amount of money expended in the 
destruction of the eggs would effect a very much larger end than 
the same amount of money spent in spraying. 

Professor Riley. I have been trying to bring out what knowl- 
edge there is as to the actual range of the insect, and my remarks 
on the possibility of stamping it out have all been based on that. 
I want to say that if the insect has spread beyond the limits in- 
dicated by Professor Shaler, and got into the larger trees, I think 
the question of stamping it out a very doubtful one. At the same 
time there is an opportunity here for the State of Massachusetts to 
make the experiment, and show what can be done by efficient 
means and intelligence. I would rather offer a higher bounty to 
every school-boy for pointing out where the caterpillars are to be 
found during two weeks in June, than for gathering the eggs. I 
believe that there is a chance of stamping it out, if it is not 



APPENDIX. xiii 

beyond the region where the trees are comparatively few in num- 
ber and not very large. 

Professor Shaler. How would it do, as one of the early steps 
in this work, to get all the information we can as to the periphery, 
and publish maps showing it? Let us ask for information as to 
the spread of the pest beyond those limits. I should hesitate 
about offering a reward for the location of the caterpillars, because 
there is the possibility of the school-boys planting them. A 
reward for the eggs is much more easy, and we could probably 
interest the school-boys in searching for them ; but it would hardly 
do to offer a reward which might serve to spread the plague. All 
these rewards for animals are very dangerous. 

Professor Riley. On general principles it is bad policy, but 
the same objection would apply to a reward for the eggs. If the 
boys once learned that they could get a certain amount of money 
for the eggs, they would not be so interested in exterminating them, 
and thus cutting off future revenue. 

Professor Shaler. I should state a definite reward, and not go 
beyond a certain time. 

Mr. Craig. We have two or three village-improvement associa- 
tions especially to take care of the trees. We extended an 
invitation to the citizens to take part in the work, and they were 
to notify certain committees wherever they found any eggs. This 
was done to a large extent, and I think it aided the commissioners 
very largely in finding out where the moths were. 

Professor Shaler. You can tell us about the extent of the pest 
in Medford. Over about how large a territory did it extend? 

Mr. Craig. More or less from the Maiden line over to Arling- 
ton. 

Professor Shaler. About a mile and a half in the worst- 
infested district. 

Professor Riley. What was the result of the commission's 
work? Are the eggs found abundantly in that neighborhood? 

Mr. Craig. I don't believe there are one-tenth the eggs there 
were when the commission commenced. 

Professor Riley. What was the result of the commission's work 
last year? Was it appreciable on the number of eggs known to 
have been there? 

Mr. Craig. Yes, certainly. I differ from you two gentlemen 
about destroying the eggs. I think it was the means of destroy- 
ing a great many of the pests. On many trees they were con- 
trolled by gathering the eggs. 

Mr. Sessions. I have no scientific knowledge on the subject, 
but it seems to me the first and most important thing we have to 



xiv THE GYPSY MOTH. 

do is to find the outside line, even if we don't do any more than 
that in one season. The old commissioners claim that they have 
found it ; our first business should be to verify that. 

Professor Shaler. Did they make a map ? 

Mr. Sessions. I think not. 

Mr. Scudder. How do they know the moth wasn't blown fifty 
miles away by a storm ? 

Professor Shaler. It may have been ; but it is a strong point 
in our favor that after the creature has been twenty years on the 
scene it still has a tolerably distinct periphery. 

Professor Riley. That is what I have based my recommenda- 
tion to exterminate it on. I should not like to see the attempt 
abandoned, but my remarks have all been made with a view of 
economizing means and time in one effective effort to exterminate 
it. All these other measures will come in if we have to deal with 
the pest as a permanent thing among us. As a mere State meas- 
ure, with a view to not having the unenviable reputation of having 
given a pest to the rest of the country or done nothing to prevent 
its spread, Massachusetts has an excellent opportunity of showing 
what may be done by intelligent, concentrated effort. All other 
means are puerile as compared witli destruction by the arsenicals. 
All other means are now abandoned in fighting the canker-worm, 
the codliug moth and some other insects, and intelligent spraying 
at the proper time has come to be looked upon as the most efficient 
means of protection against these insects. My idea is that what 
you ought to do is to employ a sufficient force of intelligent per- 
sons to scour that whole region in the month of June, and indicate 
every plant that has a brood upon it. 

Professor Shaler. Suppose you had a hundred persons search- 
ing at the same time, what general instructions could you give 
them in determining what trees were infested ? 

Professor Riley. The insect is gregarious, and therefore con- 
spicuous. There is no reason why intelligent search should not 
detect it, even on the highest trees. 

Professor Shaler. How much time could you reckon on hav- 
ing for your search after the creature came out ? 

Professor Riley. I should say you could count on ten days 
after it was hatched. Its gregarious nature makes that feasi- 
ble. 

Professor Shaler. How much time is there before it begins to 
spin? 

Professor Riley. I believe it takes three or four weeks. 

Professor Fernald. I think it highly desirable to make the 
attempt to stamp it out. I don't know that it can be done, but it 



APPENDIX. xv 

is worth trying. If we cannot exterminate it, the other excellent 
remedies can be used for holding it in check. 

Professor Shaler. Had we not better wait until we can strike 
a hard blow, and do the best we can this year with prevention? 

Professor Riley. I am strongly of opinion that you had better 
not wait. Some contingencies may arise to give it a sudden 
impetus. I would adopt the auxiliary methods of introducing 
parasites, etc., and I would also have a special committee author- 
ized to inspect all nursery stock that goes out from the infested 
region, and not allow it to go until passed upon by competent 
men. 

Professor Fernald thought the Federal government might take 
charge of the work. Professor Riley stated that he would be glad 
to assist in any way possible, but that since the establishment of 
State experiment stations the Federal government felt it had no 
further function in the States, so far as local insects are concerned. 
Professor Shaler thought the State of Massachusetts should make 
the fight itself, and only ask for Federal aid in case it could not 
exterminate the pest. Twenty-four thousand dollars were on hand, 
and he thought that twenty-five thousand dollars or fifty thousand 
dollars more could be counted on from the Legislature. 

Mr. Scudder. I don't understand the force of the arguments 
used by my neighbors on either side [Professors Riley and Fernald] 
of delaying the work by not taking the eggs at present. Why do 
they want all the caterpillars out that they can get, in order to ex- 
terminate them? 

Professor Shaler. It is a question of seeing them, I believe. 

Mr. Scudder. I understand. But, if you destroy so manj r 
eggs that say only one tree out of five is attacked, you have to 
deal with only one-fifth as many trees in spraying. 

Professor Riley. I want to tell Mr. Scudder just why I rather 
urge the policy I have advised. First of all, it is from the politi- 
cal side. If you ask for an appropriation to stamp it out, you 
must do your best to stamp it out. As Professor Fernald has 
suggested, it is simply a question of means, and I would not think 
of asking for less than one hundred thousand dollars, and I would 
concentrate that where it would do the most good. Killing the 
eggs is frittering the money away at a time when it is not of so 
much value as if concentrated. Secondly, I have little faith in the 
destruction of eggs in this case, where they are laid on so many 
different objects. I remember distinctly a little cedar tree not 
more than six feet high in my own grounds that was attacked by 
the bagworm. I thought I would see whether I could not clear 
them off. I worked for two consecutive months picking off from 



xvi THE GYPSY MOTH. 

the tree the issue of not more than two females. Almost daily I 
went to that tree, and found fresh specimens that I had overlooked 
the day before. Yet in the Smithsonian grounds I have absolutely 
stopped similar injury on larger trees in a few minutes by spraying. 
It would have been no use, in my judgment, to have attempted to 
eradicate them by hand picking. Suppose you have somebody 
climb a tree and gather twelve batches of eggs, but he fails to get 
the thirteenth. It will cost no more to spray a tree for the thirteen 
batches than it will for the one. 

Professor Shaler. When I came here I was strongly in favor 
of offering a reward for the eggs, but I admit I am shaken now. 

Mr. Scudder. I don't think you can get sufficient force to spray 
the trees thoroughly in the time allowed. 

Professor Shaler. I think we shall have to ask the Agricultural 
College to lend us say eighty or a hundred of their young men for 
this work. 

Mr. Sessions. There are many people living in the neighbor- 
hood of this spraying who claim that it was of no sort of value. 
Do any of these gentlemen believe that? 

Professor Riley. I think the reasons that have been given ex- 
plain why they had that experience. It was simply due to the 
impurity of the Paris green and the imperfect manner of applying 
it. You will always have more or less of failure until you put this 
matter into the hands of men who can give their whole time to it 
during that period. Only those men should be emploj^ed who 
have ability and experience ; and one man, particularly, should be 
engaged to superintend the whole work, and as many other com- 
petent persons as possible. 

A tree fifty feet high is very easily sprayed. If the caterpillars 
could not be killed by spraying, it would be better to cut the trees 
down over the whole of the Middlesex Fells. It pays better to 
make one grand effort than to fritter your energies away over a 
number of years, and then fail. The Board in control of the 
w r ork should control everything. If Paris green is used, it should 
all be issued by the Board, after being tested. 

Professor Shaler. I should like to ask your opinion, gentle- 
men, whether any considerable risk to health is to be apprehended 
from this large use of arsenic in the country. Is there any risk of 
poisoning the water or of poisoning animals or men ? 

Mr. Appleton. The committee on public health is having an 
extended hearing on the use of arsenicals. 

Professor Riley. If the spraying is copious and careless, 
which is unnecessary, there is danger of stock feeding upon grass 
which has been so impregnated, but there is no necessity for that. 



APPENDIX. xvii 

The spraying should be of such a character that there would be 
comparatively little falling from the tree or shrub sprayed. 

Professor Shaler. Have you known of any cases of poisoning 
in persons employed in spraying ? 

Professor Riley. No, I have seen none, but I have known of 
cases where negroes would sit on the back of a mule with spray- 
ing pumps, going through cotton fields, and carelessly allow the 
water to fall on them. I have known them to become sore in the 
groin, but never knew of a fatal case. 

Mr. Appleton. The spraying is washed off by the first rain, 
of course? 

Professor Riley. It should not be. The whole tree is en- 
shrouded in a vapor which is all-sufficient, and which is more 
effective than a more copious spraying. 

Professor Shaler. Is there any particular form of engine 
which will give that form of spraying? 

Professor Riley. There are various spraying devices in use, 
depending largely on the height of the vegetation. If you want 
to throw to any great height without the use of ladders, you need 
a spraying device that will throw a strong jet. In almost all 
cases you can use the cyclone nozzle in its Vermorel modification. 

Mr. Scudder. I should like to say before going that it does 
not seem to me likely that the thing will be exterminated, but 
that it can be held in check for many years. The reason why I 
don't think it can be exterminated is because we have not enough 
persons used to looking for the caterpillars to examine the trees 
and say for certain that there are none there. I do think, how- 
ever, that it can be held in check. 

Selectman W. A. Peirce of Arlington said they had very little 
trouble with it in his neighborhood. The sentiment of the people 
there was in favor of the continuation of the work. 

Mayor Wiggin of Maiden. We went through and marked 
every tree that was infested, and then went through again and 
sprayed them. The trees were not so infested as to be particu- 
larly noticeable. 

Mr. Gould of Melrose. The selectmen did not believe there 
were any gypsy moths in then* town. As far as he knew, the 
people were not disturbed by their presence. They would be 
glad, however, to have the inspectors go through the town and 
look for it, and would gladly second their efforts. 

Professor Shaler. I think it would be a tax of probably more 
than one hundred thousand dollars annually if not checked. 

Professor Riley. There is no question of that, if it is allowed 
to take its course. That is what makes it so vitally interesting to 



xviii THE GYPSY MOTH. 

me, and why I am so impatient of any efforts to simply check it. 
I have nothing to say about checking it ; I speak for stamping it 
out. Mr. Scudder simply says he doesn't thiuk it will be exter- 
minated. As to how much of any given territory one individual 
is capable of critically examining, a man who is capable of dis- 
tinguishing between this caterpillar and others, doing nothing 
else, would, in my judgment, be able easily to go over a square 
mile of ground a day, except in dense forest. 

Professor Shaler. I don't think so ; nothing like it. If the 
work was done closely (and two together would do better work 
than one ) , my impression is they would be doing good work to 
get over a hundred acres a day. 

Professor Riley. Well, say a hundred acres — 

Professor Shaler. If we could get from the college say forty 
young men as inspectors, we would have four thousand acres a day 
inspected, and my impression is that the region covers about ten 
thousand acres. That area can be thoroughly inspected by twenty 
parties of selected men doing nothing else. They should mark 
the infested trees and plat them on a map. As we are no longer 
a paid commission, I would devote that money to experts. We 
want the best expert we can select to superintend the actual appli- 
cation of the remedies. When a tree is marked as infested, let it 
be numbered so and so ; and when it is sprayed, let an account 
be taken of that tree, so that by some system of checking we can 
find whether every tree has been disposed of or not. 

Professor Riley. The suggestion seems to me eminently wise. 
But I suppose you could get the leading citizens in a community 
interested also? 

Mr. Sessions. I don't believe you can get the college boys to 
come. 

Professor Riley. Not if you paid them? It would be an ex- 
cellent education for agricultural students ; and if you offered 
them a hundred dollars each, you would have no difficulty in get- 
ting them, I think. 

Professor Shaler. What month should the work be clone in? 

Professor Riley. As far as I can learn, the month of June. I 
believe that about the second week in June will be the time to 
strike, after having made all your plans, got your forces ready and 
trained your men. It may be that the thing is not practicable, 
but I can see nothing impracticable. It is simply a question of 
money and men. After this one thorough effort you need not ask 
for another appropriation ; everybody will be interested, and then 
you could afford to offer a big reward for any eggs that might es- 
cape. The attempt is well worth making. 



APPENDIX. xix 

Mr. Sessions. A great obstacle is in procuring help you can 
depend on. 

Professor Riley. Let me make one other suggestion. While 
the infested area is stated in the rough at fifty square miles, from 
what Professor Shaler said there would probably be large portions 
of it that would require nothing but inspection. Now, wherever 
there are large trees difficult to climb, I would certainly take the 
precaution to ring or band them, because that will prevent any 
stray caterpillars from climbing up those trees. No caterpillars 
will ascend such trees ; and if any escape, you will find them at 
the foot of the trees. European experience shows this. 

Professor Shaler. Where can we get on the track of the mixt- 
ure they use in Europe for that purpose ? 

Professor Riley. You can use printers' ink for that purpose. 
In Newark I recommended the use of the fire department for 
spraying certain very tall elm trees. 

Professor Shaler. I presume we could make such an arrange- 
ment with the fire departments. 

Mr. Craig. We have an engine that could be so used. 

Professor Riley. I would modify my objection to egg collect- 
ing just so far that in the case of large trees it would be advisable 
to do the work prior to aestivation. I think boys could go over 
them, and in this direction winter work would be advisable. It 
would also be advisable to have these large trees very carefully 
inspected for the eggs ; but I do not believe you would be justified 
in attempting to destroy the eggs over the whole area. 

Professor Shaler. Is the energy of diffusion and the tendency 
of the females to travel at all proportioned to their numerousness ? 

Professor Riley. Yes ; it is a general principle with insects 
that, in proportion as they become unduly multiplied, the migra- 
tory instinct is developed. 

Professor Shaler. So that, in so far as we reduce the number 
in a given field, we tend to reduce the expansive energy? 

Professor Riley. Without doubt. 

Professor Shaler. And, therefore, if we fail to exterminate it 
this year, we shall at least diminish its expansive energy. 



xx THE GYPSY MOTH. 



Appendix B. 



REVISED RULES AND REGULATION'S ADOPTED BY THE STATE 
BOARD OF AGRICULTURE, 

Under Chapter 210, Acts of 1891. 

Rules and Regulations for the Public. 

1 . All persons are forbidden by law to remove the eggs or 
any other form of the gypsy moth from one city or town to 
another, and are requested to exercise care against so transport- 
ing the gypsy moth on teams and carriages. 

2. All persons are forbidden to remove from any locality in 
the towns of Medford, Everett, Chelsea, Maiden, Melrose, Cam- 
bridge, Winchester, Somerville and Arlington any hay, manure, 
wood, bark, trees, rags, lumber or shrubbery of any kind, without 
a written permit from the Board of Agriculture. Persons desiring 
to remove such materials will notify the field director, 13 Stan- 
wood Hall, Maiden. 

3. All persons are forbidden to in any way imitate or erase the 
marks employed by this Board to designate trees, fences or build- 
ings which are infested or have been cleaned. 

4. All vehicles leaving the above-named district may be 
stopped by the officers of the Board and delayed until their con- 
tents have been sufficiently inspected to determine the fact that 
they are not liable to transport the eggs or any other form of the 
insect. 

5. No person shall trim, scrape or cut down trees within the 
district known to be infested by the gypsy moth, or remove them 
without first notifying this Board, and having said trees thoroughly 
inspected, and, if found infested, cleaned under its direction. 

The eggs of the gypsy moth are frequently scattered abroad by 
scraping the trees and by careless gathering ; therefore, all per- 
sons except the authorized agents of this Board are forbidden to 
remove the eggs of the gypsy moth from the trees or other objects 
upon which they may have been deposited, or to remove such 
infested trees or objects from one place to another. 

Land owners and tenants are requested to destroy all other 
forms of the moth which they may find upon their premises. 



APPENDIX. xxi 

6. All persons, upon notice, are required to confine their dogs 
while the agents of this Board are at work upon their premises. 

7. Owners or tenants are requested to gather and burn all 
rubbish and useless material upon their premises that may provide 
nesting-places for the gypsy moth, and to fill with cement or other 
solid material all holes in trees upon their premises. 

8. All persons are requested to keep the windows of their 
houses protected by screens during the summer mouths, as the 
moth often lays its eggs in houses, wherever it can gain admittance. 

9. All persons having reasonable cause to believe that the 
eggs, caterpillars or other forms of the gypsy moth exist on or 
about their premises are earnestly requested to forthwith notify 
E. H. Forbush, director, by letter addressed to his office in Mai- 
den, Mass. Information of the moth's existence in isolated or 
unsuspected localities will be gratefully received, and all persons 
furnishing such information will receive the thanks of the Board. 

10. Notice is hereby given that it will, in some cases, be nec- 
essary to remove boards from fences or buildings. In all cases 
such boards will be eventually replaced, if possible, without 
damage to the structure. Attention is called to the fact that any 
damage done by the agents or servants of this Board, in the work 
of exterminating the moth, may be recovered under provisions of 
section 2, as above printed.* 

Attention is also called to section 6, as above printed,* which 
sets forth the penalties for obstructing any servant or agent of the 
State Board of Agriculture under this act. 

11. Courteous and considerate conduct is expected of all 
agents and employees of the Board. Complaints in writing con- 
cerning any infraction of this rule should be sent to the director, 
and will be heard by him or the committee. 

E. W. Wood, 
Augustus Pratt, 

F. W. Sargent, 
J. Gr. Avert, 

S. S. Stetson, 
Wm. R. Sessions, 
Committee of the State Board of Agriculture. 

Rules and Regulations for Agents and Employees. 
It shall be the duty of employees to familiarize themselves with 
the rules governing the gypsy-moth work. The violation of any 
of the rules will be sufficient cause for discharge at any time with- 
out notice. 

* See page 47. 



xxii THE GYPSY MOTH. 



General Rules. 

1. No person will be employed or retained who is known to 
use intoxicating liquors as a beverage. 

2. Smoking is strictly prohibited during hours of labor. 

3. Courteous and considerate conduct is required of all agents 
and employees of this Board. 

4. All agents and employees (unless otherwise ordered by the 
director) must wear at all times during working hours the uniform 
caps and badges issued by the quartermaster. 

5. Employees must provide themselves with the uniform pre- 
scribed by the State Board of Agriculture and said uniform must 
be worn during working hours. 

6. No employee shall sign the paj^-roll for another unless he 
has a written order from the person for whom he signs. Said 
order must be made out on one of the blanks furnished by the 
Board and must be sent with the pay-roll to the director's office. 

7. Superintendents and inspectors are empowered to recom- 
mend men for employment, promotion or discharge. Delinquents 
should be sent with a sealed note of explanation to the office. 

8. If an employee is unsatisfactory in any way, the inspector 
or other officer immediately in authority over him should inform 
him at once of the fact and note it on the report of that day. 

9. If men are delayed in getting to work by the lateness or 
negligence of an inspector or a teamster, or if any inspector shall 
order or allow his men to cease work before the regular hour, said 
inspector or teamster will have the hours lost by himself and the 
men deducted from his time, and superintendents shall report the 
facts of the case. 

10. Employees before signing receipts for tools should assure 
themselves that the numbers on the tools and receipts agree. 

11. If a transfer of tools from one employee to another is made 
in the field, the tools will remain charged to the man who took 
them from the storehouse, unless a record of such transfer is taken 
in or mailed to the office within twenty-four hours of the time of 
such transfer. Unless such notice is received, the employee to 
whom the tools were originally charged will be held responsible 
for them. 

12. Inspectors may use time cards, when necessary, as a 
medium for ordering tools. 

13. Drivers and owners of wagons are responsible fos tools 
committed to their charge. 

14. An employee leaving the service of this Board must at 
once return to the quartermaster all property of the Commonwealth 



APPENDIX. xxiii 

which has been in his charge. Otherwise, the full value of the 
same will be deducted from his wages then due. 

Mules for Inspecting Sections, Marking Trees and Destroying 

Eggs. 

15. Each inspector must keep in his note-book a complete 
record of all work done in his section. This book is to be returned 
to the director's office when called for, and to be left there when 
the inspector's term of office expires. 

16. Each inspector must carry his section map with him in the 
field and locate upon the map (by means of such marks as may 
be ordered by the director) each tree or locality that he finds 
infested. 

17. Each tree found infested must be at once marked with such 
characters as may be designated by the director, the mark to be 
on the trunk at three points equidistant from each other and five 
feet from the ground. 

18. When a tree is found infested which has been marked in a 
previous season, the new mark is to be placed two inches above 
each of the latest marks. 

19. Each object on which egg-clusters of the gypsy moth are 
found in ' ' outside towns " must be marked with a spot of white 
paint the size of a ten-cent piece, this spot to be within an inch of 
each egg-cluster. Egg-clusters found in woodland must be sur- 
rounded with a ring of white paint. 

20. No trees on highways, in orchards or upon grounds about 
residences are to be cut, burned or trimmed unless it is found to 
be actually necessary. In every case where a large branch is cut 
off the stump must be covered with coal-tar. Trees must not be 
cut down unless written permission is obtained of the owner, or 
unless it is so ordered by the director. 

21. Each inspector will pay special attention to the trees and 
shrubbery along the lines of railroad in his territorj 7 . The grounds 
around railroad stations must be carefully inspected. 

22. Inspectors are not to call at the office except to leave re- 
ports, or unless by special order of the director. 

23. Each inspector or acting inspector having charge of two 
or more men will form his men in line and call the roll at seven 
a.m. at the place where he begins work. He will again form 
them in line and call the roll at the close of the day's work. 

24. When the roll is called at night inspectors must state dis- 
tinctly to their men the point at which they will call the roll on 
the following morning, and any employee who fails to answer this 
roll-call will not be allowed full time. 



xxiv THE GYPSY MOTH. 

25. Employees will exercise great care that they do uot carry 
living larva? from place to place either on their vehicles and cloth- 
ing or in any receptacle. 

26. When employees under the direction of an inspector are 
obliged to injure or destroy any property, or when property is 
accidentally destroyed, or accidents of any kind occur, the facts 
must be reported at once to the inspector, and he must make a 
note of the same in his report, giving an estimate of the amount 
of damage done and names of all witnesses. 

27. Inspectors must note (and ask their men to note) and 
state in their reports the language and means used by persons ob- 
structing their work. 

28. When troublesome dogs are encountered inspectors may 
require the owners to confine them, under penalty of the law. 

29 . Employees must not leave ladders standing or lying by the 
curbstone in the street. They must be taken down when not in 
use and removed to some safe place. Care must be used in 
handling ladders and also in climbing trees, not to break or other- 
wise injure the branches. 

30. Employees must exercise great care in blazing trees. The 
inner bark should never be cut. 

Fires. 

31. No fires shall be kindled except by order of the division 
superintendent. 

32. Superintendents will demand that due caution is observed 
in the kindling and management of fires. They will see that the 
necessary appliances are at hand for the management and extin- 
guishing of all fires ordered kindled. Inspectors in charge will be 
held responsible for the proper management of fires, or if fires are 
left at the close of the day's work without being extinguished. 

33. No fires are to be built upon sidewalks, or near the curb- 
stones in the streets. 

Spraying. 

34. Inspectors must notify pedestrians not to walk under trees 
which are being sprayed, and must avoid spraying on vehicles. 

35. In spraying always station the tank to windward of the 
sprayers, so that the spray may not blow over it. 

36. Before beginning work on an estate inspectors must re- 
quest occupants to take clothing from lines, close windows and 
remove anything that may by any possibility be injured by 
spraying. 

37. Employees must use great care not to injure lawns, flower- 
beds, vegetable gardens or other property. 



APPENDIX. xxv 

38. Inspectors are to handle and mix poisons. 

39. The solution in the tank must be constantly stirred from 
the time it is first mixed until the tank is empty. 

40. Tanks must be fastened on the wagons in such a way that 
they cannot be overturned. 

41. If, during the spraying, a tree is found infested and un- 
marked, it must be marked. Each time a tree is sprayed it must 
be marked with three round dots, the size of a ten-cent piece, the 
first set being placed five feet from the ground, and each succeed- 
ing set an inch above. 

42. Inspectors will carefully notice the effect of the spraying 
and record the same in their daily reports. 

43. The spray thrown on the trees must be as fine as possible. 

44. Drivers of spraying wagons, when at work, will be under 
the direction of the inspector in whose section they are employed. 
Each inspector will keep the time of his driver and report the 
same. 

45. Inspectors must, when possible, draw water from the stand- 
pipes. When hydrants are used the inspector only shall open and 
close them, exercising great caution to open and close them slowly, 
but not closing them so tightly as to prevent opening. 

46. At morning and at noon, before beginning spraying, each 
nozzle must be turned into the bottom of the tank and a full 
stream pumped for five minutes. 

Reports. 

47. The rating of superintendents and inspectors will be based, 
not only on the quality of the work done by their men, but on the 
fulness and excellence of their own reports. All reports must be 
sent to the director's office and are subject to his approval. Each 
inspector must make out his report daily and give it to his super- 
intendent, or send it to the office (by mail or otherwise) on the 
following day. Observations on the habits of the insect and other 
items of interest, and any statements or complaints by citizens, 
should be embodied in the reports. 

48. Superintendents must notice whether the streets are re- 
ported in their proper sections. 

49. Inspectors must give time of employees on each day's 
report. 

50. In case of the absence of an employee the inspector must 
give the reason (when known to him) for such absence on the 
report of the day when such absence occurs. 

51. Inspectors must observe the printed headings on reports 
and fill spaces reserved under the same. 



xxvi THE GYPSY MOTH. 

52. Inspectors must give the correct street and number of each 
building and estate inspected and the full name of the property 
owner or tenant. 

53. If at work in two or more sections in a day, inspectors 
must make a separate report for each section. 

54. The name of the inspector, if at work, must appear in the 
employees' column. 

55. When a man enters the employ of this Board the inspector 
with whom he first serves shall make note of it at the time on his 
daily report. 

56. Each inspector will designate on each day's report and 
time card the exact point at which he will begin work on the next 
working day and on what street and in what direction be will 
move ; also the exact hour and place of roll-call and the place 
designated for roll-call the following morning. 

57. Whenever a marked tree is cut the inspector in charge 
shall incorporate the fact (giving marks) in his daily report. 

58. Inspectors will report as trees all young growth above 
three inches in diameter. 

59. When brash is cut and ground burned over inspectors will 
report in square yards the area cleared daily. 

60. If men are sent away on special duty by an inspector he 
must state the reason on his report and mark time card " see 
report " opposite such names. 

61. Superintendents, special inspectors and all other assistants 
in the field must state on their daily reports when and where they 
meet their men ; and inspectors must also note on their reports 
the time of such visits. 

Per order of the committee, 

E. H. Forbush, Director. 




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APPENDIX. xxvii 



Appendix C. 



AN EXTRACT FROM A DESCRIPTION OF SECTION 8, MEDFORD, 

AS IT APPEARS IN THE SECTION BOOK, SHOWING THE 

CONDITION OF THAT SECTION AND THE WORK DONE IN 

IT IN 1891. [THIS SECTION INCLUDES THE GLENWOOD 

DISTRICT.] 

Medford, Section 8. 

Boundaries. 
Commencing at a point on the centre line of Main Street, in 
front of the Boston & Maine station of the Medford branch rail- 
road ; thence easterly by the centre line of said railroad to the 
centre line of the main line of the Boston & Maine Railroad ; thence 
northerly on said main line of railroad to a creek flowing under 
said railroad (the centre line of said creek being the boundary 
line between Medford and Everett) ; thence northwesterly and 
northerly by said boundary line to the centre line of Salem Street 
to Valley Street ; thence westerly by said Valley Street to Forest 
Street ; thence southerly by the centre line of said Forest Street 
and Main Street to the point in front of the railroad station, the 
point of beginning. 

Description. 
Section 8, Medford, contains the cottage formerly occupied by 
Mr. L. Trouvelot, the gentleman who imported the gypsy moth 
and accidentally liberated it here. The southwestern angle of the 
section near the Medford branch railroad station constitutes a 
large part of the business portion of the town. It is quite com- 
pactly built up with dwelling-houses, shops, stores, etc. The 
traffic with outside towns is considerable. The principal thorough- 
fare, Salem Street, is the high-road to Maiden and the towns to 
the east. Forest Street, which forms the western boundary, is 
much used for carriage, driving. On the Medford branch railroad 
and within this section are the Park Street and Glenwood stations. 
Near these stations and on the intervening land along the line are 
the homes of small householders and people whose business is in 
Boston. Here, as elsewhere through much of this section, each 
house has its lot of land and generally a small garden or orchard. 



xxviii THE GYPSY MOTH. 

The streets are usually well provided with shade and ornamental 
trees, many of which are large and stately elms. In the spring of 
1891, when work was first begun by the commission, the greater 
portion of this plain, including the swamp, was covered with 
a young coppice intermingled with bushes and undergrowth. 
Near the southern border of this tract the Anderson Pressed 
Brick Company erected extensive works in 1886 on the ground 
used more than twenty years ago by Trouvelot for his silk-worm 
pasture. 

Gravelly creek runs through the western part of the section near 
the Forest Street boundary. The northern boundary of the sec- 
tion lies close to the rocky ledge which marks the beginning of the 
Middlesex Fells. Near the centre where the insect was first 
colonized there is a large tract of woodland suitable for the shelter 
and propagation of an insect pest. Upon the west several streets 
much travelled, and with gardens and orchards on either hand, lead 
toward the centre of the town. On the south is a railroad which 
terminates at the heart of the infested district and is supported by 
a traffic with Boston. The principal thoroughfare connecting 
Medford with eastern towns runs through the heart of the section. 
Another large thoroughfare marks its eastern border, and a stream 
which flows north or south as the tides rise and fall rises in the 
section and flows to the Mystic River. Here we have all the 
requisites for the sustenance of the iusect and all facilities for its 
transportation in all directions. 

The commission appointed by Governor Brackett to " check the 
spreading and secure the extermination " of the gypsy moth un- 
doubtedly destroyed large numbers of moths in this section by 
burning, by scraping off the eggs and by spraying ; yet when the 
agents of the Board of Agriculture first entered the section, in 
March, 1891, its condition was, to say the least, alarming. Some 
parts of the brush and woodland were so infested with the eggs of 
the species that it was utterly impossible with the men and means 
at our command to destroy them by hand. There were acres of 
ground where egg-clusters were numerous. Many eggs were laid 
on the ground and were found in great numbers in excavations 
where people had dug out clay or sand. A stone wall which was 
torn down (the lower surfaces of the rocks being thereby exposed) 
presented a remarkable spectacle. There being no large trees 
near the wall, it formed a refuge and concealment for the moths 
that fed on the neighboring bushes and saplings. On one rock 
over one hundred large egg-clusters were counted. When the 
number of eggs contained in a single egg-cluster is considered, it 
is apparent that millions of caterpillars would have hatched in 



APPENDIX. xxix 

this wall had the eggs not been destroyed. The trunks of some 
of the trees were actually yellow with egg-clusters. Though the 
insects were not distributed equally over the entire section, there 
were many places where eggs were found in sufficient numbers to 
have let loose a destroying host upon the entire neighborhood. A 
large per cent, of the yards within one-half mile of the Trouvelot 
house were thus infested. 

The yard of the Anderson Pressed Brick Company includes a 
part of the wooded section hereinbefore described. At the present 
time the eastern portion of the yard is covered with a scattered 
growth of young oaks and bushes. Near the buildings and 
attached to them on the east are several sheds in which are piled 
many thousands of the finest quality of pressed brick. East of 
these are several detached sheds also filled with brick. Near 
them is a pile of broken bricks about thirty yards in length, 
fifteen feet in width and ten feet in height. These sheds and the 
brick-bat pile are among the oaks, the pile being heaped against 
some of the trees. When the work in the brick yards was begun 
by the commission on March 21, 1891, the entire premises were 
infested by the gypsy moth. About three hundred thousand 
bricks were stacked in the sheds and two hundred thousand out- 
doors under the trees. The crevices between these bricks gave 
opportunity for the moths to deposit their eggs. The bricks 
under the sheds near the buildings had not been much frequented 
by the moth, but three-fifths of those under the trees were more or 
less covered with eggs. The egg-clusters were found on the 
ground and under the floors, on the sides and under the roofs of 
the sheds, under the stumps and about the roots of trees, on their 
trunks and limbs and in almost every conceivable sheltered place. 
As the infested bricks were likely to be transported in all direc- 
tions, the danger of the distribution of the moth by this means 
appeared great. A capable man was at once stationed in the yard 
to examine all bricks sent out. The finest quality of bricks sent 
out previous to this time had been shipped to a distance. Most 
of them were used for fireplaces and were cleaned by the brick 
company before shipment, and in this way all eggs were probably 
taken off. Many localities to which bricks had been shipped were 
afterwards examined. The work in this yard was pushed with 
the greatest energy. Two hundred and thirty-two thousand one 
hundred and ninety-five bricks were examined, and all those 
infested were cleaned and the eggs burned. The shed most badly 
infested was burned. The floors, roofs, etc., of the others were 
torn up wherever necessary, and the eggs taken from them. 
Some of the trees near the shed were cut down and burned. The 



xxx THE GYPSY MOTH. 

brick-bat pile was surrounded by a board fence eighteen inches 
high. This was covered with tarred paper, and before the cater- 
pillars began to hatch in the pile the paper was covered with a 
mixture of pine tar, printers' ink and crude petroleum. This 
fence the young caterpillars were unable to scale. The trees in 
the brick yard were inspected and the eggs on them destroyed. 
Fire was run through the underbrush, but this did not kill all the 
eggs. One section of the yard was burned experimentally by 
spraying the ground with crude petroleum after the brush had 
been set on fire. On this section no signs of the caterpillars 
were seen during the year. In other sections, where some eggs 
survived the burning and hatched, all vegetation was sprayed 
with Paris green several times during the season. At the end of 
the season it was difficult to find any sign of the moth in the yard. 
Trees and bushes were cut down over a tract of one hundred acres, 
and fire was run over it. Any spot that escaped the fire was 
thoroughly burned by the use of crude petroleum. 

The inspection of the towns on the border line of the infested 
district occupied so much time in the spring of 1891 that it was 
found necessary to neglect until egg-hatching time a large tract 
near the centre of the district in Maiden and Medford. Time was 
found, however, to inspect the large trees along the highways and 
railroads. The eggs found on them were destroyed and the trees 
were banded with tarred paper, which was kept covered with the 
mixture used in the brick yard. This prevented the larva? from 
ascending these trees, and reduced the danger of their being 
carried out of the district. Most of the trees in the section were 
sprayed two or three times during the season with a mixture con- 
taining Paris green, in some places where badly infested they were 
sprayed four times ; nearly all vegetation, in fact, was sprayed. 
Holes in the tree trunks which offered hiding-places for the larvae 
were filled with cement. Burlap bunds were put about the trees 
after the caterpillars began to cluster, and by these means the vast 
increase was kept down. 

As soon as the female moths had laid their eggs and died, a 
small force of men began destroying the eggs. It was soon 
noticeable that, while vast numbers of last season's egg-clusters 
which had hatched were found, very few newly laid clusters ap- 
peared. Every nook and crevice was searched with the greatest 
care to discover and destroy all traces of the moth. While the 
leaves remained on the trees, buildings, fences, woodpiles and all 
hiding-places near the ground were searched. As the leaves fell 
the trees were examined and cleaned of eggs. Where the trees 
were thickly infested the leaves were raked up and burned ; thus 



APPENDIX. xxxi 

every possible effort was made to exterminate the moth by gather- 
ing the eggs. 

After going over the entire section carefully, an estimate of the 
number of eggs found was made. Comparing this with the 
estimated number found in the spring, it was seen that the number 
found in the fall was about twenty per cent, of the number found 
in the spring. The data for this estimate were very complete, and 
were taken from the daily reports of the inspectors. 



xxxii THE GYPSY MOTH. 



Appendix D. 



REPORTS OF ENTOMOLOGISTS WHO VISITED THE INFESTED 
REGION IN 1893. 

Report of Dr. A. S. Packard of Brown University, late of 
the United States Entomological Commission. 

Providence, R. I., June 19, 1893. 
Prof. C. H. Fernald. 

My Dear Sir : — Having been asked to give my impressions 
of the work now being done at Maiden and vicinity in exterminat- 
ing the gypsy moth, I will say that it made a good impression on 
me, and I have no adverse criticisms to make. Mr. Forbush seems 
exactly adapted for the work intrusted to him. I was struck 
with the ability shown in organizing and systematizing the whole 
work, and the readiness and interest shown by the men under Mr. 
Forbush. The office and its system, the storehouse and its appa- 
ratus, interested me very much, and the new and ingenious devices 
for spraying and in other ways destroying the eggs and worms. 
It seems to me the work is practical and thorough throughout, 
and must bear good fruit this season. 

In the short time I spent I saw nothing to find fault with, but 
much to commend. I say this without wishing to merely say 
something pleasant, but because I mean it. 

Yours very truly, 

A. S. Packard. 



Report of Dr. J. A. Lintner, State Entomologist of New 

York. 

Office of State Entomologist, Room 27, Cafitol, 
Albany, June 22, 1893. 
Prof. C. H. Fernald. 

My Dear Sir : — The two days that I passed last week, in 
compliance with the request of the gypsy moth committee of the 
State Board of Agriculture and of yourself, in inspecting the oper- 
ations of the committee through its director, Mr. E. H. Forbush, 
were highly gratifying and satisfactory to me. I was not pre- 



APPENDIX. xxxiii 

pared to see that such progress had been made toward the exter- 
mination of the notorious gypsy moth. It was a surprise to me 
that in the brief space of three years the fearful ravages of the 
insect as described to me and as pictured in photographs could 
have been reduced to such a comparative harmlessness that to the 
ordinary observer no indication of its presence was visible, and 
that in a ride of an entire day through several of the " infested 
towns," including a visit to localities which had been frightfully 
scourged, not a single example of the caterpillar was found by 
me, although diligent search for it was made. 

How a work of such magnitude, extending over so large a terri- 
tory, could have been accomplished, was a wonder and an enigma 
to me, until I became acquainted with the means by which it had 
been brought about. These are, in part : — 

First. Your work at the insectary is largely supplementing 
that being conducted at the Maiden headquarters. I regard it so 
exceedingly valuable and so absolutely essential to the best results 
in field work, the one to check and therefore to aid the other. 

Second. The committee, I am confident, have been both wise 
and fortunate in their selection of Mr. Forbush as director of field 
work. I think that I estimate correctly when I say that he is 
eminently fitted for the important and responsible position. A 
high degree of judgment and discretion has evidently been exer- 
cised in the selection of those employed by him and the retention 
of those best qualified for the duties assigned them. The execu- 
tive ability displayed by him in the organization of his force, its 
direction, guidance, supervision, equipment, accountability, etc., 
seems to me remarkable, and to go far toward the accounting for 
the singular success that has attended his administration. 

Third. The " storehouse" greatly interested me. It may prop- 
erly be called an " arsenal," for it is furnished with all the 
appliances needed for conducting in the most effective manner the 
warfare in which you are engaged. In it are found not only all 
of the more important instruments and materials that economic 
entomology had tested in former years but many new ones, called 
into use for the first time, as the need had become apparent and 
the ability for their conception and production was at command. 
With such means, as above indicated, your State, which has 
been liberal in its appropriations, has a right to expect ample 
returns. It will not be disappointed, for you have already accom- 
plished more than could have been reasonably expected. 

I trust that your Legislature will see the wisdom of continuing 
the work under suitable appropriations, until the extermination of 
the insect has been attained, or at least until it shall have been 



xxxiv THE GYPSY MOTH. 

reduced to entire harmlessuess, and in position never again to 
develop in injurious numbers or to invade other States. 

I have been asked to offer such criticisms or suggestions as I 
might deem it proper to make. I have found nothing to criticise, 
but, on the contrary, have received instruction from what I saw. 

Under the permission given, I will offer two suggestions : — 

1. As what may be called the mechanical details of field work, 
as burlapping, liming, spraying, egg collecting, etc., are steadily 
diminishing, there will be the greater need (as well as the oppor- 
tunity) of scientific work, to round up, as it were, the labors of 
the committee, to aid in its completion, to render it available for 
future use wherever the necessity may arise in this or similar 
insect invasions, and to make such a contribution to science as 
Massachusetts has ever been ready to do when the occasion has 
offered. 

I would, therefore, suggest (and recommend, if I dare venture 
to do so) that the committee, if possible, avail themselves of more 
of your time and service. Your habits of thought, observation 
and study seem specially fitted to the work that you are now con- 
ducting for the committee. Further, the experience that you have 
gained is of so great value that it should not be lost to them. I 
do not, however, see how this could be brought about under your 
existing relations with the college and agricultural station. I am 
sure that there is an ample field for your entire service. If the 
committee could offer you a sufficient inducement, is it not pos- 
sible that, while retaining your connection with the college and 
station, you could be released from the discharge of the duties, 
say for two or three years, and devote yourself wholly to the 
gypsy moth ? So positive am I of the utility of such an arrange- 
ment, that I sincerely hope that it may be accomplished. 

2. Just at this stage of the committee's work I would sug- 
gest that the cultivation of the parasites of the gypsy moth be 
entered upon and conducted with all the knowledge and skill that 
can be brought to bear upon it. Far more is to be hoped from 
this than from the costly and problematical search for and impor- 
tation of its European insect enemies. Nearly a score of native 
parasites are already known to prey upon it, and we may expect 
this number to be materially increased. Something like the fol- 
lowing method of cultivation might be pursued : — 

Collect the pupa? as soon as they are to be found, so as not to 
give opportunity for the escape of the earlier maturing parasites. 
None should be destroyed, but carry all carefully to headquarters 
at Maiden, suitable provisions having been previously made for 
their reception and care. 



APPENDIX. xxxv 

If 80,000, as reported, were collected last year, perhaps from 
15,000 to 20,000 might be secured this year. Arranged in a 
single layer, a case not exceeding twenty-five square feet of area 
would be ample for them, and leave space at one end for feeding 
larvae. 

By means of cold storage, delay the development and emergence 
of the parasites until larvae are in readiness in which they may 
oviposit. 

Egg-clusters collected this season shall be so regulated by 
temperature that they will give out their larvae as soon as food is 
obtainable for them. 

With the feeding larvae in one part of the case with the pupae, they 
will at once be found by the parasites and all of their eggs deposited 
in them if the larval supply is proportioned to their need. 

When the parasitism is finished, the larvae may be fed in con- 
finement to maturity, if practicable, provided that conditions 
favorable to the prevention of disease or other fatality can be 
given them ; or they may be transferred to isolated trees selected 
for the purpose, where they may complete their growth and be pro- 
tected from destruction by birds by inclosing the trees in netting. 
The following season the parasites, unless desired to extend their 
multiplication by again rearing them in confinement, may be per- 
mitted to escape and seek their prey abroad. 

The parasitized caterpillars might be conveyed to the localities 
where the parasites are the most needed. 

Gathering the parasites from the case after their death would 
give every species which was parasitic on the larvae and pupae 
(except such as may have emerged from the larvae), and their 
proportionate number, from which the most efficient could be 
ascertained. Examination would also show the proportionate 
number of pupae that had been destroyed by parasites. 

The above plan may not have been properly digested by me, 
and there are no experiments of the kind to serve as a guide. So 
far as I know it has not been attempted on a large scale (the 
multiplication of icerya parasites in California was somewhat 
similar) , but if done with the knowledge that you could bring to 
bear upon it, I am sanguine of its success. Possibly by this 
means only can the desired extermination of the gypsy moth be 
attained. 

If, under the existing law, the carrying of the living insect 
from one town to another is prohibited, amendment for the above- 
named purpose could no doubt be secured. 

Very truly yours, 

J. A. LlNTNEK. 



xxxvi THE GYPSY MOTH. 



Report of Prof. John B. Smith, D.Sc, of Rutgers College, 
State Entomologist of New Jerset. 

New Brunswick, N. J., June 20, 1893. 

Dear Dr. Fernald : — Since my return to New Brunswick I have 
been thinking over what I saw of the work of the gypsy moth 
committee near Maiden, Lynn and Swampscott, and with the 
lapse of time my admiration for the work accomplished has in- 
creased rather than diminished. When I received your invitation 
I was, I think I can truly say, free from actual prejudice, yet with 
a disposition to believe that the work of the committee was 
palliative merely, and that actual extermination was impossible, an 
impression to which I had given public expression. I am pleased 
to say that I have seen ample evidence to induce a change of 
opinion, and my belief is now that if the committee is as well 
supported as it deserves to be it will accomplish the end for which 
it was created. With this expression of my present belief, you 
will understand that my suggestions are not in the nature of 
adverse criticism. 

First, concerning the experiments in progress at Amherst, at 
the present time. These consist of a test of the action of certain 
insecticides on larvae of all ages, and in contemplation are experi- 
ments concerning possible parthenogenesis, fixiug the relative time 
of issuiug of the sexes from one batch of eggs and the effect upon 
the fertility of the eggs of close breeding, — that is, between 
males and females bred from the same egg-mass. 

All these experiments are not only of the highest scientific 
interest, but also of the utmost practical importance. 

If parthenogenesis is possible, the danger of spreading the 
insects by carrying off single specimens is vastly increased, and the 
most stringent measures to prevent such distribution are justified. 
While parthenogenesis in the Lepidoptera is extremely rare, yet 
cases have been recorded in the same natural group to which this 
insect belongs, and the inquiry is therefore by no means a merely 
curious one. 

Fixing the relative time of the emergence of the sexes of the 
same brood is of very great importance, for, if males and females 
issue at such intervals as to make it unlikely that they can pair, 
the danger from the distribution of even several larvae from the 
same batch of eggs is materially lessened. 

The determination of the effect of in-breeding is equally im- 
portant, for much the same reason. 

Finally, the experiments with insecticides are of peculiar interest, 



APPENDIX. xxxvii 

from the fact that the caterpillars seem unusually resistant to the 
action of arsenic in doses fatal to most of the insects known to us. 

There is one criticism to be made on all the above experiments : 
they are on too small a scale to render the results altogether convinc- 
ing and they are made in the wrong place at Amherst rather than at 
Maiden, Lynn or elsewhere in the infested region. The extreme 
caution necessary to prevent the escape of specimens of the larvae 
prevents the practice of certain lines of out-door work, the results of 
which would supplement the in-door or laboratory experiments. 

I would therefore suggest that the experiments now carried on 
at Amherst be duplicated or transferred to some point within the 
infested district where material is more abundant, and where there 
is no danger of introducing the insect into new localities. 

These experiments must of course be made by a trained ento- 
mologist, or by a competent man under detailed instructions. By 
all odds the most satisfactory plan would be to have you carry on 
the experiments yourself, for they would then command universal 
acceptance and would be generally regarded as conclusive. 

The result of the insecticide experiments thus far is so unusual 
that I would recommend a further series of experiments to deter- 
mine exactly what becomes of the arsenic eaten by the insects ; 
whether it is absorbed or whether it is excreted, and how much 
arsenic an insect will contain when its intestinal canal is filled with 
poisoned food and excreta therefrom. This could be done by 
feeding larvae on leaves sprayed with a maximum amount borne 
by the foliage for say three or four days, and then substituting 
fresh food free from poisou. A chemical test should be made 
thereafter every day or every day or two, to ascertain the presence 
or absence of arsenic in the larva? . Microscopic examinations of 
the digestive tract of poisoned larva? should also be made, and 
should be compared with that of healthy larvae, to ascertain 
whether any lesion were caused that might result in a degenerated 
adult. The excreta of larvae fed upon poisoned food should also 
be analyzed to determine the amount disposed of in this way. 

This is of course suggestive merely ; but in my opinion the 
present occasion is an unusually good one to gather a mass of 
facts whose importance to economic entomology it would be dif- 
ficult to estimate. 

If I had reason to speak in approbation of the line of experi- 
ments laid out by yourself at Amherst, I found very much more 
to admire in the infested district, in the actual field work under 
the direction of Mr. Forbush. The mere organization of the force 
and the plan of the work is excellent ; as to the results of the 
methods adopted, the fact that in the entire infested district 



xxxviii THE GYPSY MOTH. 

visited by me — Maiden, Lynn and Swampscott — only a single 
half-grown lai'va was discovered speaks loudest. 

I was extremely interested in the office organization, in which 
the system of entering and classifying reports enables the director 
and the members of the committee to determine at once the exact 
condition of affairs in any district. The notes of observations 
made by inspectors are many of them of the greatest interest, 
and merit editing by an entomologist capable of recognizing facts 
and separating them from inferences made by the observer. 

The inspection of the tool-house was a revelation in the variety 
of apparatus it afforded, all of it adapted to the special end in 
view. The practical value of all the apparatus is obvious, and 
while for an orchard the spraying outfits might be considered 
clumsy and somewhat wasteful, yet when the character of the 
work is considered the apparatus designed for the fruit grower is 
manifestly insufficient. A most commendable feature in the work 
has been seeking out means of taking advantage of the peculiarities 
of the insect's habits, which is, after all, the most philosophical 
way of accomplishing the work in baud. 

It would be altogether too long a task to go into details con- 
cerning the outfit of insecticide machinery, and I need only say 
that I can find absolutely nothing to suggest in the way of improv- 
ing the methods of work. 

The force under the direction of Mr. Forbush has accomplished 
wonders, and I feel now that there is very good reason for the be- 
lief that the gypsy moth can be exterminated, provided the means 
are furnished by the Legislature of Massachusetts in as liberal a 
spirit at least as past appropriations have been made. 

I have been asked to give an opinion on the feasibility of intro- 
ducing European parasites of this insect, to keep it in check. I 
feel very decidedly that this would be money wasted. This and 
its ally, the Nonne, are frequently destructive in Europe, and if 
its parasites do not succeed in mastering it there, there is no reason 
for believing that they can do better here. 

Nature never works for the extermination of any of its creatures, 
and if parasites ever exterminated their hosts the parasites them- 
selves would be exterminated for the want of food. A balance is all 
that nature aims for. A parasite which would be able to exterminate 
the gypsy moth in this country must be one that would prey on this 
one insect only ; and even then it is very problematical whether 
the result would be very satisfactory, for to enable the parasites 
to do their work, artificial means of destroying the larvae would 
have to be abandoned for fear of killing the parasites as well. 

I am very strongly of the opinion, therefore, that nothing can 
be gained by an attempted introduction of parasites. 



APPENDIX. xxxix 

The oft-cited case of Vedalia destroying the cottony cushion 
scale in California can have no application to this case, for the 
circumstances there were so peculiar that they can rarely be dupli- 
cated, and are not similar here. 

I am asked to express an opinion as to the work done and to be 
done by the committee. I can only repeat what I have already 
said, — the work done by the committee as at present organized 
is admirable, and I am unable to point out a method in which it 
could be improved. 

Both the entomologist and the director thoroughly, understand 
the problem, and are working for success, — a success that I now 
think they will attain. 

As to the work yet to be done, I am not in a position to give an 
opinion, because I had no time to cover the entire ground. From 
what I could see at Maiden, Lynn and Swampscott, I believe that 
for at least two years more a full force of men should be em- 
ployed, using the methods that have proved so successful and 
working from the outer limits toward the central district. 

The most useful men should in all cases be retained from year to 
year, for they will be worth at least double the sum any new man 
could be valued at, and will know just exactly what is to be done 
in all cases and just what to look for. After a few years the force 
of men could be safely reduced to the inspectors and a few ordi- 
nary workmen, whose principal business would be a continuous 
examination of the once-infested district, prepared to destroy any 
isolated brood that may have escaped ; and finally this force could 
be reduced to the director and a very few inspectors, who, with 
the experience gained, could easily command the entire region 
until lapse of time proved the insects exterminated. 
Very truly yours, 

John B. Smith. 

Dr. C. H. Fernald, Entomologist, Gypsy Moth Commission, Amherst, Mass. 



Report of Prof. Clarence M. Weed, D.Sc, of the New 

Hampshire College of Agriculture and the Mechanic 

Arts, Entomologist of the Agricultural Experiment 

Station. 

Hanover, N. H., June 16, 1893. 

To the Gypsy Moth Committee. 

Gentlemen : — In response to the invitation extended by you 
through Professor Fernald, I recently visited the various depart- 
ments of gypsy-moth work, and beg leave to inform you of the 
impressions thus received. 



xl THE GYPSY MOTH. 

I first inspected the work in progress at the insectary at Am- 
herst, and found that a series of experiments with remedies was 
being conducted under the most careful conditions ; in fact, I have 
never seen a series of similar experiments carried on in so large a 
scale in so thoroughly scientific a manner. They ought certainly 
to furnish reliable results, which will be of great value outside of 
the gypsy-moth work. 

I next went to Maiden, and in company with the other visitors, 
Professor Fernald, Mr. Forbush and Mr. Reid, looked over the 
ground carefully. The general impression received was very 
favorable as to the amount and methods of work. The results 
already reached seem to be remarkable, and I was greatly surprised 
at the scarcity of gypsy caterpillars. The methods of fighting the 
pest have evidently been developed along with the knowledge con- 
cerning it, and are well adapted to the end in view. 

The only suggestion I have to make concerns the lack of ade- 
quate facilities for studying the life history of the pest at head- 
quarters. It seems to me that if a room adapted to the purpose 
could be set apart, and a man of entomological training be detailed 
to make out the biological points yet in doubt, valuable results might 
be reached. I should suppose that it would hardly be necessary to 
call in an entomologist of note if Professor Fernald is willing to 
supervise the work of the one detailed to carry on such observations 
and experiments. In fact, the results would have an added value 
if carried on both at Maiden and Amherst under one direction. 

I was especially interested to learn of the results that have been 
reached with the arsenate of lead. Even if it does not kill gypsy 
caterpillars as quickly as does Paris green, it seems probable that 
it will make a valuable insecticide for many other purposes. 

Thanking you for the opportunity you afforded, and assuring 
you of whatever support I may be able to render, I am, 
Yours respectfully, 

Clarence M. Weed. 



Report of Dr. H. T. Fernald, of the Pennsylvania State 

College. 
State College, Centre County, Pa., June 19, 1893. 

To the Gypsy Moth Commission. 

Gentlemen : — In accordance with your request, extended to 
me by Prof. C. H. Fernald, I have examined the work in progress 
at Maiden and Amherst, and am both interested and pleased with 
what I have seen. 



APPENDIX. xli 

Previous to ray visit to Maiden I felt some doubt as to whether 
it was possible to exterminate the gypsy moth, as I had had 
some previous knowledge of it and of its ravages in Massa- 
chusetts, being at Amherst when it was first reported to the ex- 
periment station there in 1889, and having carefully looked over 
the matter at that time. Since my visit a careful considera- 
tion of the methods used and of the results already obtained 
has convinced me that extermination is not only probable, but 
certain, if the work be prosecuted for a sufficient length of 
time. 

On one or two points I have gathered impressions which may 
perhaps be worthy of mention here : — 

1 . I think that the position so far held by the committee with 
reference to the effect of parasites is a wise one. I have never 
heard of a case where an insect was exterminated by its parasites, 
the relation of the two forms at any one time being, in numbers, 
very close. A reduction in the numbers of the host is always 
followed by a similar reduction in the numbers of the parasites, 
leaving to those individuals of the host which have escaped an 
opportunity for rapid and unchecked increase until overtaken by 
a corresponding but later increase in numbers of the parasites. 
For this reason parasites cannot be relied upon to do the work 
needed in the case of the gypsy moth. 

2. The method of burning over infested areas in connection 
with burlapping the trees seems to me to be a most effective 
method of procedure if the precaution of burning for a sufficiently 
great distance beyond the limits of the infested area be carefully 
observed. My impression is that the edge of the burned area 
should always be at least two hundred feet outside these limits, 
as far as these can be ascertained. 

The work so far accomplished shows on its face that the 
methods in use are the result of experience, and that they are 
most efficacious. 

It seems to me that two things are greatly to be feared : — 

1. That the time is near when searches with negative results 
may tend to produce carelessness on the part of the searchers. 

2. That the apparent disappearance of the moths may lead 
the Legislature into the error of abolishing the committee at the 
time when its work will show the fewest results, but will in reality 
be the most valuable, — in fact, would be absolutely necessary to 
insure the prevention of some future invasion. 

The work done by the committee in the way of testing insecti- 
cides in the field at Maiden and in the laboratory at Amherst is 
of great value, and the importance of learning with the greatest 



xlii THE GYPSY MOTH. 

accuracy just how successful each method is, cannot be overesti- 
mated. The care with which the experiments at Amherst are 
conducted guarantees the accomplishment of this most important 
task, while the discovery of a new insecticide with the properties 
which the arsenate of lead apparently possesses must certainly be 
worth more to the State than all the money it has spent for the 
extermination of the gypsy moth. 

Yours respectfully, 

H. T. Fernald. 



APPENDIX. xliii 



Appendix E. 



REPORTS OF ENTOMOLOGISTS WHO VISITED THE INFESTED 
REGION IN 1894. — OPINION OF THE UNITED STATES EN- 
TOMOLOGIST. 

Report op Dr. George H. Perkins of the University of Ver- 
mont, Entomologist of the Vermont State Agricultural 
Experiment Station. 

Burlington, Vt., July 10, 1894. 
Prof. C. H. Fernald. 

Dear Sir : — In accordance with your invitation to visit the 
region infested by the gypsy moth, I went to Maiden, as you are 
aware, and through the very cordial assistance of both yourself 
and Mr. Ware, assistant director, was enabled to see in a most 
complete and satisfactory manner the appliances used and the 
various methods of using them. 

I wish to express my appreciation of the thorough and careful 
manner in which the work was being done, and the evident desire 
of those engaged in it to execute the trust committed to them as 
faithfully and economically as possible. No work of the sort 
which I have ever seen or heard of has impressed me as favorably 
as did that of the officials engaged in the work of exterminating 
the gypsy moth. 

The whole nation should be grateful to the committee for what 
it has already accomplished ; for it is my belief that, had not the 
work been so well done in Massachusetts, the insect would ere this 
have spread beyond the borders of that State and now threaten 
the whole land. It is most gratifying to find, instead of this, that 
the ravages of the moth have been very much reduced by the 
efforts of the committee. 

No one interested in economic entomology can investigate the 
work in office and field without at once discovering that a vast 
amount of very useful information has been gathered which should 
not on any account be lost to science. On this account it is very 
greatly to be desired that as full and complete a report as possible 



xliv THE GYPSY MOTH. 

of the work of the committee be published, for much that such a 
report would contain would necessarily be of general and permanent 
value. 

The question has been asked, Is it possible to exterminate an 
insect which has become so abundant as the gypsy moth ? Before 
I visited the infested region, and saw what had already been done, 
I was quite doubtful as to the expediency or the possibility of 
extermination ; but after investigation I thought differently. It 
seems to me very clearly the wisest and most economical course, 
for the present at any rate, to continue the work as it is now going 
forward, and aim at extermination. The men and the methods 
now employed are so successful that it would be unwise to discon- 
tinue them for several seasons to come. 

It also seems to me that the functions of the committee might 
be very advantageously extended, so that in their discretion they 
could direct their destructive agencies against such other insects as 
might be easily taken in hand. 

When passing through some of the towns infested by the gypsy 
moth we noticed many trees the foliage of which had been wholly 
destroyed by the canker-worm ; and many of these trees could 
have been sprayed by those engaged in spraying neighboring trees 
for the moth at small cost of time or money. 

It was very evident that private enterprise could not be 
depended upon to deal with these pests. It is my own conviction 
that the most efficient and the cheapest method of dealing with 
any insect which has become numerous and destructive is that 
adopted in the case of the gypsy moth, not leaving to private citi- 
zens the too great task, and thus ensuring failure, but bringing 
the authority and the resources of the State to the work, and 
carrying it forward to success. 

Is it not probable that, had the gypsy moth not been stayed in 
its destruction, the loss to property through the destruction of 
shade and fruit trees would have been more than the cost of 
extermination has thus far been? 

It is to be hoped that the work so well done thus far will not 
now be suffered to lag through lack of either funds or popular 
support. There is every reason for continuing it, while to stop or 
reduce it would be a great calamity. 

I have not been asked to praise the work of the committee, but 

rather to suggest improvements in their methods, and to criticise 

whatever I might find deserving it. I have no criticism to offer, 

nor am I able to make suggestions other than those given above. 

I am, sir, very truly yours, 

Geo. H. Perkins. 



APPENDIX. xlv 



Report of Prof. F. L. Harvey of the Maine State Col- 
lege, Botanist and Entomologist of the Maine Experi- 
ment Station, Orono, Me. 

To the Members of the Gypsy Moth Committee of the State Board of 
Agriculture of Massachtisells. 

Gentlemen : — In compliance with your courteous invitation 
(extended to me through Prof. C. H. Fernald) "to inspect the 
work of the gypsy moth committee and give my impressions and 
advice," I visited Maiden the latter part of July, and spent two 
days examining the work of the committee in the office, labora- 
tories and field. Through the courtesies of Director E. H. For- 
bush and others of the department every opportunity was afforded 
me to gain a thorough knowledge of the scope and character of 
the work of the committee. 

I went to Maiden with an entirely inadequate conception of the 
territory affected, and the stupendous undertaking of the com- 
mittee to reduce or exterminate the gypsy moth. I first visited 
the office, and was surprised by the ingenuity and thoroughness 
displayed in keeping the field notes and indexing them for ready 
reference. A mass of information regarding the habits, natural 
history and anatomy of this insect has been accumulated by 
Professor Fernald, Director Forbush and their assistants. This 
seems so important that for the good of entomological science it is 
hoped it may be sifted by a competent entomologist and published 
as a monograph by the committee. The pains taken in examining 
the men for field work and the almost military exactness required 
of them in their labor and reports reflect great credit upon the 
organizing ability of the director, and speak much for the 
efficiency of the service. 

The work being done in the laboratory and insectary upon the 
life-history of the moth, its parasites and histology, and upon 
remedies, was timely and thorough. I was especially interested 
in the histological work, conducted by Mr. A. H. Kirkland, to 
determine if possible what becomes of the arsenical poison the 
full-grown larvae are known to eat with impunity, and also the 
trap experiments under the direction of Mr. Kirkland. 

The storehouse for apparatus and supplies impresses one with 
the magnitude of the work, and is instructive in the novel 
apparatus invented to fight this pest. 

The results obtained in the experiments on insecticides, by Mr. 
F. C. Moulton, are most important, and bid fair to be of great 
usefulness to economic entomology. 



xlvi THE GYPSY MOTH. 

The field methods of searching for the eggs, larvae and pupa?, 
the burlapping of the trees and the careful burning of infested 
areas was thorough and practical. 

Upon the whole, the methods which have been born of experi- 
ence and adopted by the committee for coping with the pest 
impressed me as ingenious and effective. I have no criticisms to 
offer upon the work of the committee, and regard the results 
obtained as marvellous. 

Entomologists are generally agreed that it is impossible to 
exterminate an insect by means of its parasites, so all that can be 
hoped for in this direction is uncertain aid in holding it in check. 
Whether it is possible to exterminate an insect by persistent and 
thorough hand-picking, use of insecticides and fire is problematical, 
because it has never been tried. It is a plausible problem, which 
we hope, for the good of economic entomology, the gypsy moth 
committee may have the opportunity to settle. By the efficient 
work of the committee, in three years' time, this insect, which was 
legion and doing great damage over a wide area, has been reduced 
beyond detection by common observation. We spent a whole day 
in the field, and, though constantly on the alert for specimens, 
saw only four male moths and no larvae, pupae or eggs. So thor- 
oughly has the work been done that intelligent people in the dis- 
trict wrongly regard the work of the committee accomplished. It 
is the scattering colonies, the last one per cent., that will demand 
more thorough work than the other ninety-nine per cent. , and your 
Legislature and citizens will need to be thoroughly impressed with 
this fact. 

Two policies present themselves : first, whether an attempt be 
made to fight the moth to the finish ; second, whether an attempt 
be made to merely keep it in check, and prevent an increase to 
harmful numbers. 

The gratifying work of the committee so far would suggest 
continuance in the good work, with the idea of extermination. 
This would absolutely require the employment of a force of men 
large enough to keep the whole infested area under constant sur- 
veillance for some time. The present number of men employed 
seems to me to be inadequate, as large areas in the infested dis- 
trict have to be neglected while inspection is going on in others. 
Unless a large force can be kept constantly employed for some 
years, the idea of extermination will have to be abandoned by the 
committee. 

If the second policy be adopted, then the work of the commit- 
tee for the present is practically done. Yet a permanent force 
would be needed to keep the area under occasional surveillance) 



APPENDIX. xlvii 

and its energies directed to checking local outbreaks. This would 
be an interminable job, constantly menaced with the danger of 
the pest spreading over large areas to adjoining States, until so 
widely disseminated as to be beyond human power to control. It 
would seem to me to be wiser to attempt the extermination of the 
pest while in its greatly reduced numbers by the adoption of a 
liberal financial policy, than to drop the work and in a decade or 
sooner have it to do all over again. 

We regret to learn (unofficially) that naturalists are breeding 
this pest for purposes of study outside of the Commonwealth of 
Massachusetts, in defiance of the strict laws regarding its dissem- 
ination. 

I heard the committee criticised by citizens and others because 
they would not destroy other injurious insects besides the gypsy 
moth in the infested district. We understand this criticism to be 
unjust, as the Legislature confined the duties of the committee 
strictly to the suppression of this one insect, and to use the money 
to destroy the others would be a perversion of funds. 

That it would be a wise policy for every State to have an en- 
tomological commission, with duties as broad as the requirements 
of economic entomology, we have no doubt. The fact that the 
gypsy moth committee has paid strict attention to business is the 
reason why they have in such a short time accomplished so much. 

In closing, I desire to thank the committee for the opportunity 
offered me to study the life-history of this insect, and to become 
familiar with the ingenious and effective methods used in coping 
with it. I hope the committee will receive the financial support 
from the Legislature that will enable it to succeed in this stupen- 
dous undertaking, which does not alone interest Massachusetts 
but also the adjoining States and the whole country. 
Respectfully submitted, 

F, L. Harvey. 



Report op Prof. John H. Comstock of Cornell University, 
late United States Entomologist. 

Ithaca, N. Y., July 17, 1894. 

Mr. William R. Sessions, Secretary of the Committee on the Exter- 
mination of the Gypsy Moth of the State Board of Agriculture. 
Sir : — In compliance with the request of your committee, trans- 
mitted to me through Professor Fernald, I visited the region 
infested by the gypsy moth, and spent several days studying what 
is being done towards the extermination of this species. During 



xlviii THE GYPSY MOTH. 

the greater part of this time I was accompanied by Professor 
Fernald and Mr. E. H. Forbush, who explained to me very fully 
the details of the work. 

I was filled with admiration of the work that is being done by 
these gentlemen, and, although I have given the matter very care- 
ful thought, I am unable to suggest any changes in their methods. 
It seems to me that the methods they are following are the best 
possible, so long as the object of the work is the extermination of 
this insect. 

But, after going over the infested region, I have come to 
have grave doubts as to the advisability of attempting to exter- 
minate this pest. I am not prepared to say that I consider exter- 
mination impossible, but it seems to me that the attainment of this 
desired end is highly improbable. It is true there are certain 
peculiarities in the habits of this insect that give hopes of the 
possibility of extermination. Thus the slowness with which the 
species spreads naturally, owing to the fact that the female does 
not fly, and the fact that the larva in its later stages descends from 
the trees and hides during the day-time, rendering it possible to 
trap it, greatly facilitate the work of destruction. On the other 
hand, the wide range of food plants, the extent of the area in- 
fested, including as it does large forests, and the ease with which 
the species may be artificially spread by means of vehicles, all 
combine to make the task a very great one. Still, if you could be 
provided with sufficient funds extending over a sufficiently long 
period, I believe these difficulties could be overcome. 

But I feel that this is too much to hope. If at this time, so 
soon after the terrible ravages of the pest, the Legislature appro- 
priates less than two-thirds of the sum which your committee, after 
careful investigation, deems necessary to carry on the work, it is 
hardly probable that succeeding Legislatures would furnish the 
means necessary to carry this work to a conclusion, involving as it 
would a large outlay for many years after the insect had ceased to 
be a pest. As I do not believe that the financial support would be 
furnished you, I respectfully suggest that you consider the advisa- 
bility of adopting a different method of combating the pest. Much 
of the work that is being done now would be unnecessary if the 
object was merely to keep the insect from being unduly destruc- 
tive ; and, if there is no hope of your receiving the support nec- 
essary to exterminate the insect, the continuance of the present 
methods would certainly involve a large unnecessary expenditure. 

It is probable that if your warfare against this insect was re- 
stricted to those localities in which its injuries are of a serious 
nature, its natural enemies would greatly increase and tend t« 



APPENDIX. xlix 

keep it in check. Already a considerable number of parasites is 
known to infest it. There will be a tendency for them to increase, 
so that in time serious outbreaks of this pest will probably be only 
occasional and in limited areas. Such outbreaks could be easily 
subdued. 

While I believe that a change in the object of the work of your 
committee seems imperative, I would not consider for a moment 
the giving up of your warfare against the pest, but would advise its 
continuance in the following manner : I would suggest no change 
in the organization for carrying on the entomological work of the 
State. A committee of the State Board of Agriculture, consti- 
tuted as is your committee, seems to me to be the most appropri- 
ate organization for this purpose. I would, however, recommend 
the broadening of the scope of the work of this committee, so that 
it should have authority to deal with any serious outbreak of insect 
pests. I will not presume to indicate in detail the method of con- 
ducting this work, beyond suggesting that in their more general 
features the horticultural laws of the State of California might 
serve as a model. 

Very respectfully, your obedient servant, 

J. H. COMSTOCK. 



Extract from the President's Address by L. O. Howard, 
Entomologist of the United States Department of Agri- 
culture, DELIVERED BEFORE THE SlXTH ANNUAL MEETING OF 

the Association of Economic Entomologists, Brooklyn, 
Aug. 14, 1894.* 

The work upon the gypsy moth, by the way, which has been 
done by the State of Massachusetts since 1889, is one of the most 
remarkable pieces of work, judging by results, which has yet been 
done in economic entomology. The operations have been carried 
on by a committee of the State Board of Agriculture, and the 
means have been furnished by large annual appropriations by 
the State Legislature. Three hundred and twenty-five thousand 
dollars have already been appropriated. 

A territory comprising something over one hundred square miles 
was infested by the insect, which occurred in such extraordinary 
numbers as to destroy many trees and almost to threaten the ulti- 
mate extinction of living vegetation, not only within the infested 

• Insect Life, Vol. vii., No. 2, page 69. 



1 THE GYPSY MOTH. 

territory, but in all localities to which it might spread. It is 
unnecessary to detail the steps by which relief was brought about. 
Mistakes were undoubtedly made at first, and it is to the work of 
the present committee that the main credit is due. The infested 
territory has been reduced by one-half, and within the districts in 
which the gypsy moth at present exists it is, practically speaking, 
a comparatively rare species. 

The future of the insect is, however, problematical. The con- 
tinuance of sufficiently large appropriations from the State Legis- 
lature to enable the work to be carried on on its present scale is 
doubtful, and yet those in charge believe that still larger appro- 
priations are necessary to bring about extermination. They are 
confident, however, that with sufficient means the insect can be 
absolutely exterminated from the State of Massachusetts. With 
the Legislature disinclined to continue the large appropriations, 
the methods of the committee at present pursued will have to be 
seriously altered. Given a small appropriation of say $25,000 
annually, it will become necessary to adopt some law, like that 
enforced in California, whereby much less frequent inspection 
may be made, and the committee will have to rely in part upon 
voluntary observers for information. Moreover, they will be 
unable to conduct spraying operations upon a large scale, and the 
expense of the destruction of insects will have to be assessed upon 
the owners of the property upon which the insects are found, pro- 
vided such owners will not themselves undertake the destruction of 
the insects. There will be many disadvantages from such a 
course, and in the case of unproductive lands the expense will be 
so great that the owner will prefer confiscation. Between some 
such course as this and the continuance of the present methods, 
however, there seems to be little choice, since if the appropriation 
were taken away the insect will not only speedily reach its former 
destructive height, but will spread far and wide over the country. 

It may be urged that it will be only a few years before the insect 
will take its place as a naturalized member of our fauna, and will 
become subject to the same variations of increase and decrease as 
our native species, and that it will, in fact, become little more to 
be feared than species already existing with us, particularly if its 
European natural enemies are introduced. Against this view, 
however, it must be urged that the gypsy moth seems an ex- 
ceptionally hardy species, and that even in Europe it is a prime 
pest. The caterpillar is tough and rugged, and seems little sub- 
ject to disease and to climatic drawbacks, and is wonderfully resist- 
ant to the action of ordinary insecticides. The gypsy-moth larva 
will feed for days without apparent injury upon trees which have 



APPENDIX. li 

been sprayed with Paris green or London purple in a solution so 
strong as to somewhat burn the leaves. In fact, the committee, in 
the spraying which they are carrying on at present, have found it 
necessary to use arsenate of lead in as strong proportion as ten 
pounds to one hundred and fifty gallons of water. The well- 
known vitality of previously introduced European injurious in- 
sects is apparently increased to a striking degree by this species, 
while the fact that it feeds on nearly all plants renders it a much 
more serious pest than any of its forerunners. Under these cir- 
cumstances, therefore, any course other than energetic and well- 
directed effort to keep the insect within its present boundaries will 
be short-sighted in the extreme, although it is very doubtful to my 
mind whether absolute extermination will or can ever be brought 
about. 



lii THE GYPSY MOTH. 



Appendix F. 



THE DANGERS OF ARSENICAL POISONING RESULTING FROM 
SPRAYING WITH INSECTICIDES. 

Much has been written in regard to the supposed danger of fatal 
poisoning to the consumers of fruit which has been gathered from 
vines or trees which have been sprayed with arsenical mixtures. 
The fallacy of these ideas has been repeatedly shown, and it is 
now well understood that there is practically no danger of fatal 
poisoning from eating sprayed fruit. There are, however, other 
dangers, arising from the widespread and careless use of arsenical 
insecticides, which have been almost entirely ignored. Entomolo- 
gists and pomologists officially connected with the experiment sta- 
tions of the country, the agricultural press and writers of works 
on pomology and horticulture all join in recommending some of 
the most deadly poisons as insecticides ; but they add scarcely a 
word of caution in regard to their use. While the danger of acute 
or fatal poisoning, which may arise from eating or drinking food 
or liquids in which Paris green or some other form of the arsenites 
has been accidentally mixed, is occasionally pointed out, the evils 
arising from contact with the poison are seldom even noticed. 
Arsenical preparations are applied broadcast to many cultivated 
crops, and few if any precautions are taken against their effects 
on the human system. Paris green is commonly sold without any 
restrictions whatever, though fatal cases of accidental poisoning 
from its use have been frequently chronicled.* 



* " Next to arsenious oxide, arsenite of copper gives rise to the largest number of 
cases of acute arsenical poisoning. This compound forms the whole or a part of 
the pigments known as Scheele's green or Paris green, Schweinfurt or emerald green 
(aceto-arsenite of copper) . When pure, these pigments contain from fifty-five to 
sixty per cent, of arsenious acid, to which their poisonous properties are mainly due. 
During the past few years arsenite of copper has been sold extensively, under the 
name of Paris green, for the purpose of killing potato bugs. Owing probably to 
the ease with which it can be obtained, it has given rise to a considerable number of 
cases of suicidal poisoning. Many cases of accidental poisoning have resulted from 
the use of these compounds as pigments." (Buck's " Reference Handbook of 
Medical Science," Vol. I, page 344.) 



APPENDIX. liii 

The action of arsenic upon the human system is poisonous, 
no matter how it may find entrance, whether through the skin, 
wounds, the respiratory organs or the alimentary tract. Nor are 
the symptoms essentially different, whatever its manner of en- 
trance. Thus, when applied outwardly to an abraded surface, it 
exerts a specific action upon the mucous membrane of the stomach. 
Hunter found that the stomach of a dog was considerably inflamed 
in an experiment in which he applied arsenic to a wound, the 
animal dying within twenty- four hours. In other cases, upon 
applying a bandage to prevent the dog licking the arsenic from 
the wound, Brodie found that the inflammation in the stomach was 
more acute and more immediate than when the poison was taken 
internally. 

The curious fact that the mucous membrane of the stomach 
inflames when arsenic is absorbed from a cutaneous surface or 
from a wound is explained by the absorption of the arsenic into 
the blood and its separation from the blood by the mucous mem- 
brane of the stomach, the arsenic in its passage exerting an irritant 
action. 

According to Blyth, a quack applied an arsenical caustic to a 
chronic ulcer, with the result that the patient was seized with 
symptoms of violent poisoning, and died six days after the appli- 
cation. Blyth says such fatalities are frequent. 

The injurious effects produced by the absorption of poisons 
through the pores of the skin are well known to toxicologists and 
to the medical fraternity. Cases where sudden death has been 
caused by the cutaneous absorption of deadly mineral or vegetable 
poisons are on record. A case is mentioned by Blyth of a woman 
aged fifty-one years, who died after a protracted illness, the result 
of using a solution of arsenious acid to cure the itch.* Less 
serious attacks of poisoning are not very uncommon among those 
who use arsenic, while continued exposure to the influences of 
mineral poisons often produces symptoms of chronic poisoning. 

"The arsenical pigments more frequently give rise to external 
local eruptions and chronic poisoning than to acute poisoning." f 

The first symptoms of chronic arsenical poisoning result from 
the local action of the arsenic. Externally they consist of cutane- 
ous irritations, eruptions and even ulcers on the various exposed 
portions of the body. The eruption of the face is sometimes 
so serious as to render the victim unrecognizable. Inflammation 



* " Poisons, their Effect and Detection," A. "W. Blyth. 

t " Reference Handbook of Medical Science," Vol. I, page 344. 



liv THE GYPSY MOTH. 

of the scrotum, sometimes resembling hydrocele, is a frequent 
symptom, and this inflammation extends to the adjacent parts. 
There is frequently an irritation of the mucous membrane of the 
eye, also oederna of the eyelids. This conjunctival inflammation is 
manifested by redness and an intolerance of light. Other inflam- 
mations of the mucous membrane, resulting in irritation of the 
nasal passages and throat, dry cough, loss of appetite, thirst, 
nausea, a feeling of uneasiness or pain in the stomach and 
intestines, and sometimes vomiting and diarrhoea ensue. Often 
these symptoms are not very severe, but they are sometimes con- 
tinued for a long period, and in a few cases they have resulted 
fatally. Other symptoms sometimes produced by the constitu- 
tional action of the poison are headaches, sleeplessness, muscular 
debility, emaciation, depression of spirits, neuralgic pains in 
various parts of the body, muscular trembling, occasional con- 
vulsions and paralysis of the extremities. It is said that fatty 
degeneration of the liver, kidneys and other organs sometimes 
takes place by a process analogous to that caused by the action 
of phosphorus.* 

The effects of the arsenical preparations when taken internally 
are Well known, but the dangers arising from their absorption and 
inhalation are not generally understood. Many people who have 
been accustomed to using arsenic in some process of manufacture 
or trade have occasionally suffered from acute attacks of arsenical 
poisoning without being aware of the real cause of their sufferings. 
Others, who have suffered for years from chronic arsenical poison- 
ing, being ignorant of the cause of their symptoms, have neglected 
to remove it, and have attributed their condition to other agencies 
or to disease. The inflammation of the mucous membrane of the 
nasal passages and throat is often attributed to catarrh, while 
the trouble with the stomach and intestines is usually attributed 
to dyspepsia. Amateur and professional taxidermists, especially 
those who use white arsenic in its dry form, sometimes suffer from 
all the symptoms of both acute and chronic poisoning. Not in- 
frequently the death of taxidermists is caused or hastened by the 
use of arsenic. In one case a taxidermist was rendered almost 
totally blind for a considerable period by the use of arsenic. 

Browne mentions a case of a man who formerly used dry 
arsenic in preserving natural history specimens, and whose con- 
stitution was, he says, thoroughly broken up by it. An amateur 
of long standing became paralyzed in one hand. This man was 

* " Poisons, their Effect and Detection," Vol. II, page 495. 



APPENDIX. \v 

not aware of the source of his trouble, and had never mentioned 
the fact of his using arsenic to his numerous physicians, who had 
therefore worked in the dark as to the real cause of his condition.* 
Mr. C. J. Maynard, author of the " Naturalists' Guide," " Birds 
of Eastern North America " and other works, was at one time so 
seriously affected by the arsenic used in the preparation of skins 
of birds and mammals that he was obliged to discard the pre- 
servative, suffering for several years from the symptoms of 
chronic arsenical poisoning. Workmen in factories where arsen- 
ical preparations are made frequently suffer from arsenical poison- 
ing, either acute or chronic, and fatal cases are on record. Some 
of the men employed in handling arsenate of soda, Paris green 
and other insecticides in the storehouse connected with the gypsy 
moth work have been somewhat affected by arsenical poisoning. 
The effect of poisoning from arsenical wall paper is well known. 

The cases of poisoning so far given are those of people who 
have been exposed to the dust or fumes of arsenic in-doors. It 
might be thought that persons working out of doors would not 
be similarly affected. Out-door conditions, such as atmospheric 
currents and sunlight, may lessen the danger of poison by inhala- 
tion. Yet arsenic, being chemically unchangeable and its poi- 
sonous properties not being affected by light, air or water, has 
practically the same effect when brought in contact with the skin 
or mucous membranes, whether the person using it is out-doors or 
in-doors. Among the workmen employed in the manufacture of 
an arsenical green which is obtained from arsenite of soda by 
treating it with sulphate of copper and then with pyroligneous 
acid, the symptoms of arsenical poisoning are very marked. The 
process of manufacture usually takes place in the open air. The 
evil consequences of working over the mixture appear in boils, 
pimples and an itching rash about the nostrils and in the flexures 
of the arms. In severe cases headache, thirst and nausea occur. 
Eruptions on the hands, face and other exposed parts, ulcers in 
the groin and other symptoms of arsenical poisoning by absorp- 
tion are not uncommon among those who use Paris green in the 
field, either in spraying trees or in dusting the poison over pota- 
toes or other field crops. 

In these cases poisoning is probably caused by the absorption 
through the pores of fine arsenical dust or spray, floating in the 
atmosphere, or by the absorption of particles of arsenic which 
reach the hands, face and other portions of the body in various 

. 

* Montague Browne, " Practical Taxidermy," pages 66, 67. 



lvi THE GYPSY MOTH. 

ways. The absorption of the poison is likely to be greater when 
the subject is perspiring freely, and the danger is greatest when 
one is handling a form of arsenic which is more or less readily 
soluble. Therefore the danger in handling arsenate of soda, 
London purple or white arsenic is probably greater than that in 
handling Paris green or arsenate of lead ; yet serious effects may 
in time be produced by either of these latter poisons, and they 
should be always used with the greatest care. The danger of 
poisoning by respiration is probably greatest when the insecticide 
is used in the form of a powder and thrown broadcast in air, 
although, if the poison is mixed in water and a fine spray is 
allowed to drift over the person, a small amount may be inhaled. 
In either case the effects of the poison inhaled will be felt first in 
the mouth, nasal passages and throat. 

The danger of poisoning by spraying is increased in the case 
of some individuals by their peculiar susceptibility to the effects 
of the poison. The difference in susceptibility to these poisons 
shown by different individuals under the same conditions is re- 
markable. It is possible that some persons may gradually become 
accustomed to the use of arsenic, and eliminate from the system, 
without experiencing ill effects, an amount of poison which would 
prove very injurious to others more susceptible to its influence. 
Some people who have once suffered from the symptoms of chronic 
arsenical poisoning exhibit a marked susceptibility to the effects of 
arsenic for years afterward. 

During the spraying in 1891 two cases were known where 
women, in whose faces a spray of Paris green was accidentally 
blown by the wind, were immediately affected with a burning 
sensation of the skin, followed soon after by eruptions. An 
elderly woman who was also exposed to the spray suffered from 
arsenical poisoning to such an extent that she required the services 
of a physician for a considerable period. Her symptoms appeared 
to arise from this exposure. 

It is not generally known that serious effects sometimes follow 
poisoning from arsenical spraying. Though there is ordinarily 
little danger from the spraying of a few trees, even this may be 
dangerous to one peculiarly susceptible to the action of the poison. 
In such a case complete prostration, inflammation, serious ulceration 
of the face and mouth and other parts of the body, suppuration, 
copious salivation and delirium have followed within a few days. 
A case of arsenical poisoning resulting fatally to an elderly 
farmer has recently been reported. In this case death is said to 



APPENDIX. lvii 

have been caused or hastened by his spraying orchard trees for 
several years in succession with Paris green. If the poison comes 
in contact with wounds or abrasions of the skin, ulcers are some- 
times formed which will not heal until spraying is given up. 
Symptoms of a mild form of this poisoning resemble those pro- 
duced by the poison ivy (RJms toxicodendron), and sprayers who 
are poisoned usually attribute their symptoms to that cause. 
While serious poisoning from spraying is rare, the mild symp- 
toms are quite frequently shown ; and in some cases, if spraying 
is done continuously for a considerable period of time, chronic 
poisoning will result. There is probably little danger of fatal 
poisoning except in cases of invalids or elderly people. 

In spraying with arsenites, serious effects may usually be avoided 
by using the following precautions : cover any wound or abrasion of 
the skin, so that the insecticide cannot come in contact with it ; 
when spraying with an extension nozzle or pole, use an elongated 
leather washer below the nozzle, so as to carry off the drip ; wear 
rubber clothing and a rubber or oil hat of the shape of a " sou- 
wester" or tarpaulin, and take care to stand as far as possible 
to windward of the spray. The face and hands should be thor- 
oughly washed immediately after spraying, and the entire body 
should be bathed daily. 

The usual treatment for arsenical poisoning is well known to 
medical men. An antidote for local external poisoning not gener- 
ally known is acetate of lead, commonly called sugar of lead. A 
strong solution of this in water will allay serious inflammations 
of the skin, caused by arsenical poisoning, but it should only be 
applied externally, and even then with care, as it possesses poison- 
ous properties. 



lviii 



THE GYPSY MOTH. 



Appendix Gr . 



A LIST OF RESIDENTS OF THE INFESTED DISTRICT WHO 
HAVE FURNISHED INFORMATION IN REGARD TO THE 
GYPSY MOTH IN MASSACHUSETTS. 

Statements in regard to the ravages, habits and spread of the 
gypsy moth or the work of destroying it in Massachusetts have 
been received from citizens whose names appear below. Lack of 
space has made it impossible to print these statements, but 
extracts from some of them will be found in Part I. 



Arlington : — 
Benjamin Campbell. 
H. A. Fernald. 
Chas. A. Greene, M.D. 

Belmont : — 
Mrs. Edwin F. Atkins. 
Edward W. Brown. 
W. L. Chenery. 
Thomas L. Creeley. 
Irving B. Frost. 
C. F. and R. Hittinger. 
Daniel F. Learned. 
Gilman Osgood. 
James K. P. Sargent. 
Edward Skahan. 
John W. Skahan. 
Merton Simonds. 
J. O. Wellington. 
Chas. W. Winn. 

Boston : — 
J. B. Alden. 
John A. Bruen. 
Mrs. T. J. Lane. 
A. L. McCormack. 
Wm. Tyner. 

Cambridge : — 
Wm. H. Eveleth. 



Chelsea : — 
J. T. Bond. 
Martin Curley. 
J. Waldo Denny. 
L. E. H. Jones. 
Wm. Jones. 
S. Kimball. 

Everett : — 
Timothy Murphy. 

Lynn : — 
J. G. Olin. 

Maiden : — 
Mrs. Peter Campbell. 
Michael Cleary. 
Mrs. Margaret Connell. 
Mrs. M. Cronin. 
Richard Dexter. 
Mrs. John Dowd. 
James F. Eaton. 
Mrs. J. W. Flinn. 
Mrs. Daniel Kelly. 
Wm. McLaughlin. 
T. J. Neville. 
Miss Abbie Sullivan. 
Mrs. B. Wallace. 

Medford : — 
Miss R. M. Angelbeek. 



Medford — Con. 
Mrs. J. H. Archibald. 
Geo. H. Bean. 
James Bean. 
Mrs. Wm. Belcher. 
Mrs. John Benson. 
Almon Black. 
Miss A. B. Bockman. 
Mrs. John Brown. 
Oran Brown. 
Miss Charlotte E. Camp. 

E. Clark. 
J. C. Clark. 
L. M. Clifford. 
J. S. Cotton. 
W. C. Craig. 
John Crowley. 
A. W. Crockford. 
D. W. Daly. 

J. P. Dill. 

C. R. Drew. 

Mrs. G. H. Dudley. 

Mrs. J. E. Fairbanks. 

Mrs. M. F. Fenton. 

Mrs. S. J. Follansbee. 

F. E. Foster. 
J. T. Foster. 



APPENDIX. 



lix 



Medford — Con. 
J. N. French. 
R. Gibson. 
F. M. Goodwin. 
J. 0. Goodwin. 
N. P. Hallowell. 
Mrs. I. W. Hamlin. 
J. W. Harlow. 
Wm. B. Harmon. 
Fred H. Haushalter. 
E. G. Holmes. 
John Hutchins. 
A. R. Kervin. 
Sylvester Lacy. 
Mrs. Chas. A. Lawrence. 
Edward Loeffler. 
Mrs. Thomas F. Mayo. 
Miss R. A. McCarty. 
Mrs. E. E. Merrill. 
J. C. Miller, Jr. 
A. P. Perry. 
Mrs. F. P. Peirce. 
Richard Pierce. 
Mrs A. H. Plummer. 
Mrs. M. M. Ransom. 
Wm. S. Richards. 
D. M. Richardson. 
Jotham H. Rogers. 
Mrs. E. M. Russell. 



Medford — Con. 
G. C. Russell. 
Mrs. P. N. Ryder. 
Miss Z. Sawyer. 
Japhet Sherman. 
Walter Sherman. 
Mrs. W. H. Snowdon. 
Mrs. F. T. Spinney. 
Wm. R. Taylor. 
Mrs. R. Tuttle. 
Geo. H. Webster. 
J E. Wellington. 
S. F. Weston. 
John G. Wheeler. 
Miss H. T. Wild. 

Melrose : — 
Henry Lynde. 
Mrs. E. A. Mansfield. 
Mrs. A. C. Peyser. 

Revere : — 
J. W. Copeland. 
S. S. Pratt. 
Benj. Shurtleff. 
Josiah B. Shurtleff. 

Salem : — 
Geo. W. Creesy. 

Saugus : — 
L. Mansfield. 
W. H. Penny. 



Somerville : — 
J. H. Cahalan. 
Asa Durgin. 
Thos. H. Eames. 
Sarah E. Fisk. 
Albert Kenneson. 
F. L. Newton, M.D. 
I. L. Russell. 

Swampscott : — 
A. R. Bunting. 
Jas. Pitman. 

Wakefield: — 
J. H. Carter. 
Rufus Kendrick. 

Watertown : — 
M. W. Chadbourne. 
Nathan Drake. 
J. W. Lovering. 
J. E. Skinner. 
Samuel Walker. 
Solon F. Whitney. 

Winchester : — 
Louis Goddu. 
H. W. Hight. 
Chas. R. Mason. 
W. D. Sanborn. 

Winthrop : — 
F. W. Belcher. 
Chas. Burrill. 



INDEX. 



A. 



Abundance and destructiveness of the gypsy moth, . 

Acclimation of the gypsy moth, 

Achoetoneura femaldi, ....... 

Acids used for destroying eggs, . . . 

Act to provide against depredations by the gypsy moth. 

Adviser, entomological, Prof. C H. Fernald appointed, 

iErostatic hairs, 

Africa, occurrence of gypsy moth in, . 
Agalena ncevia, ....... 

Age of egg-clusters, how determined, . 

of new colonies 

Alarms, false, 

Albrecht on distribution of gypsy moth, 

Aletia argillacea 

Algiers, occurrence of gypsy moth in, 

Alisma plantago as a food plant, 

Altum, Dr. Bernard, advice concerning importation of parasites, 

on value of birds, 

America, importation of gypsy moth into, . 

importation of English sparrow into, . 

occurrence of gypsy moth in, recorded by Professor Riley, 
American redstart attacking the gypsy moth, 

robin attacking the gypsy moth, . 
Ammonia, eggs treated with, .... 
Amount of food consumed by caterpillars, . 
Anabrus simplex, destruction of crops by, . 
Analyses of Paris green, 

of Paris green and lime, .... 

of poisoned larv as, 

Anatomy of the gypsy moth, external, 

of the gypsy moth, internal, .... 
Anderson Brick Company, shipments from, 
Anderson on ravages of gypsy moth in Shipov, 
Angelbeek, Miss R. M., statement of, 
Animals, distribution of the gypsy moth by, 

injured by spraying, 

Anisocyrta sp., 



PA«K 

40 

94 

387, 392 

63, 123, 413, 416 

36, 47 



57 

301 

267 

405 

95 

70, 80 
201 
268 
325 
267 
317 
288 
211, 232 
3 
233 
3 
208 
208 
407 
315 
206 
492 
493 
474 
339 
368 
110 
282 

27, 29 
103 
161 
375 



20. 



Ixii 



THE GYPSY MOTH. 



Anisota senatoria, 

Anisopteryx pometaria destroyed by chickadee, 

food plants of, ... 
Annual inspection, the, 
Antennae of gypsy moth, 

function of, 

Anthrenus scrophularice, damage from, 

Antinonnin, 

Ants attacking female moths, 

Apanteles, species parasitic on gypsy moth in Europe 

Apple trees attacked by gypsy moth in Europe, 

trees injured by bad pruning, 

trees, leaf area of, .... 

Appleton, F. H., at conference on gypsy moth (Appendix 

member of committee, 

resignation from committee, 

visit to Washington, 

Appropriation, balance of, on hand Jan. 1, 1894, 

efforts to secure an, from Congress, 

expended by first commission, 

expended by second commission, . 

insufficient, 

loss by delay of, 

necessity of, in order to inspect woodland, . 



A). 



PAGE 

400, 402 
204 
97 
196 
339 
356 
270 
479 

364, 380 
378 
277 
174 
495 



49, 76 
77 
83 
72 
83 
73 
73 
39, 61, 64, 69, 87, 88 
63, 68, 78, 79, 84, 85 
80 

Appropriations, yearly, 36, 39, 49, 63, 68, 77, 84 

Area, infested. See Infested region. 

leaf, of trees, 494 

spiny, of wings of gypsy moth, 341 

Argyrophylax gilva, 392 

Arlington, area of woodland infested in, 87 

gypsy moths found in, 58 

petition presented Jby selectmen of, 36 

Army worm, cyclone burner recommended against, .... 121 

gypsy moth mistaken for, 33 

Arsenate of lead, .... 69, 80, 87, 142, 143, 145, 449, 473, 449 

of soda*, experiments with, 143 

of zinc, experiments with, . . . . . . . 480 

Arsenic as an insecticide, .......... 481 

effects of , . . . . '.' '.' . . . . 162 

Arsenical poisoning (Appendix F). 

poisons, comparative effects of, 473 

effects on foliage, .."."..' 489 

spraying with, . 55, 417 

Arsenites, entomologists recommend spraying with, . . . . 45 
Ash, exempt from ravages of gypsy moth in Eussia, . . . 282 

Asia, distribution of gypsy moth in, 267 

Asilus sericeus, 392 

Aspens attacked by gypsy moth, 277 

Assembling of the gypsy moth, 342, 345 

power of pupa?, . . 363 

Atlanta Exposition, exhibit at, ' . . . 201 



INDEX. 



lxiii 



Attacus cecropia, 

promethea, ..... 
Aughey, Prof. Samuel, experiments on plover, 

on birds v. locusts, .... 
Australia, importation of rabbits into, 

importation of sparrow into, 
Avery, John G., elected member of gypsy moth committee, 



PAGE 

387, 402 
402 
204 
205 
233 
233 
84 



B. 



Bacteria, aid rendered by, .... 

occurring in larval stomach, 
Bailey, C. E., observation on birds distributing 

observation on Cimbex americana, 

observation on cuckoo, .... 

observation on downy woodpecker, 

observation on egg-feeding birds, 

observation on Theronia melanocephala, 

observation on vireos, .... 

observation on warbler, 
Baltimore oriole attacking the gypsy moth, 
Bands, burlap, 

pitch, 

raupenleim, 

tar, 

tree ink, . 

wadding, 

Barrett, C. G., on disappearance of gypsy moth 
Bavaria invaded by nun moth, 
Bay State Brick Company, shipments of wood 
Bazin on ravages of gypsy moth in France, 
Bean, James, statement of, . 
Bechstein on egg killing, 

on ravages of gypsy moth, . 
Bees, danger to, from spraying, . 
Beetles, cages for breeding, 

predaceous, .... 
Belcher, Mrs. William, statement of, 
Beling, Theodore, on methods of destroyin 
Belmont, colonies found in, 
Benson, Mrs. John, statement of, 
Benzine, eggs treated with, . 
Berlin, occurrence of gypsy moth at, . 
Bibliography of gypsy moth, 
Birch attacked by gypsy moth in Europe, 
Birds as destroyers of locusts, 

attacking the gypsy moth, 

attracted to infested localities, 

destroyed for milliners, . 

destruction of canker worms by, . 

destruction of parasites by, . 



the 



to, 



£ the 



ypsy 



inE 



nsrlaud 



ypsy mo 



moth, 



th, 



213 



64, 129, 

285, 

64, 

127, 



8, 11 



20 



19 

274, 
257- 

277, 



240, 



288 
369 
236 
379 
212 
221 
229 
376 
222 
219 
225 
167 
285 
195 
286 
128 
285 
270 
208 
111 
277 
, 29 
117 
275 
157 
384 
381 
, 26 
285 

47 
, 27 
408 
277 
■267 
282 
205 
207 
223 
243 

96 
376 



lxiv 



THE GYPSY MOTH. 



PAGK 

98, 214, 231, 235, 239 

. 232 

6, 96, 209, 228 

228 



Birds, distribution of gypsy moth by, 

European, introduction of, . 

feeding on the caterpillars, .... 

feeding on female gypsy moth, 

feeding on male gypsy moth, 

feeding on the pupae of the gypsy moth, 

folly of destroying, 

most useful as moth destroyers, . 

native, driven away by English sparrows, . 

protection of, 

that may devour gypsy moth eggs, 

value of, 

value of, in Europe, 

v. useful insects, ...... 

Black, Almon, statement of, .... 

Black-and-white warbler attacking the gypsy moth, 
Black-billed cuckoo attacking the gypsy moth, . 
Blackbird attacking the gypsy moth, . 

value of, ....... 

Black-throated green warbler attacking the gypsy moth 
Bluebird attacking the gypsy moth, 

driven away by sparrows, .... 
Blue-jay attacking the gypsy moth, 

distributing the gypsy moth, 
Board of Agriculture, State, advice of, concerning extermination, 

amount expended by, in 1891, 1892, 1893, . 

appropriations recommended by, . 

bulletin issued by, 

conference at office of, ..... 

extracts from reports of the, 

petition for an additional appropriation by the 
mittee of, ...... 

reorganization of, suggested by fm. H. Bowker 

special meeting of, ..... 

supersedes commission of 1891, . 
Boards of health, information furnished by, 
Bockman, Miss A. B., statement of, . 
Bombycidse, assembling in the, .... 
Books, section, record of infested estates kept in, 
Boston & Maine Railroad, inspection of, 
Boston, danger from traffic to, . 

gypsy moth found in, 

result of inspection of, in 1894, . 
Bowker, Wm, H., elected a member of the committee, 

reorganization of State Board of Agriculture suggested by 
retirement of, from State Board of Agriculture, 
Brackett, Gov. J. Q. A., commission appointed by, 

extract from message, 

Bradley, J. Howard, appointed commissioner, . 

Branches, how broken, 

removal of, 



20 



65-67, 78 
executive com 



228 

228 

205 

210 

234 

242 

228 

203 

284 

240 

24, 28 

208, 225 

207, 212 

207 

204 

208 

208, 218, 227 

234 

6, 207, 225 

236 

70 

74 

77, 84 

56 

45 

81, 82 



62, 68 



182. 



78 

83 

49 

47 

107 

20 

357 

52 

111 

107 

70, 80 

80 

76 

83 

83 

38 

35 

38 

174 

184 



INDEX. 



lxv 



in France 



Breeding cage for predaceous insects, 

Bremer on distribution of gypsy moth, 

Brick shipments, inspection of, . 

Bromine used on eggs, 

Brood, second, of gypsy moth, . 

Brown, Thomas, on ravages of gypsy moth 

Brown thrush attacking the gypsy moth, 

Brush,' cutting and burning, 

Brussels, ravages of gypsy moth in, 

Buffalo carpet beetle, damage from, 

Bufo lentiginosis, 

Bugs, predaceous, 

Buildings, comparison of yearly work on 

Bulletin of information, publication of, 

Bullock, Representative W. J. D., order presented 

Bunting, townee, attacking the gypsy moth, 

Burlap, . . .57, 64, 69, 79, 114, 167, 168, 169, 

Burner, cyclone, . 

naphtha, 
Burning, caterpillars killed by, 

hollow trees, . 

machines, 

of eggs, . 

of foliage by arsenites, 

pupae, 

rubbish, . 
Burrelle, on use of burlap, 



63, 



85, 



by 



170, 



57, 58, 59, 



PAGE 

384, 395 
. 267 
. 110 

125, 408 
86, 295 
. 274 

208, 225 

167, 193 

. 279 

. 270 

. 404 

241, 392 

93 

199, 200 

72 

225 

188, 213, 291, 335 
. 121 
122 

126, 165 
121 

119-121 
57, 118 
159, 491 
59 
. 193 
. 171 



34, 



56, 



87, 



c. 

Cabbage butterfly, damage from, 270 

Cadey, E. J., statement of, 40 

Cages for breeding predaceous insects, 384, 395 

Calcic chloride, eggs treated with, 409 

Calosoma calidum, 381, 383 

frigidum, 383 

inquisitor, 287 

scrutator 382 

sycophanta, 287, 385 

Camp, Miss C. E., statement of, 26 

Camponotus pennsylv aniens, 364,381 

(herculaneus,) ......... 405 

Campoplex conicus, 378 

difformis, 378 

Canker worms destroyed by birds, 96,204,219 

destroyed by spraying, 140 

importation of sparrows, against, 233 

influence on destruction of gypsy moth caterpillars, . . . 222 

Cannon, Hon. George Q., on cricket ravages, 206 

Carabus serratus, ........... 383 

Carbolic acid for destroying eggs, 123 



lxvi THE GYPSY MOTH. 

PAGE 

Carbon bi-sulphide, eggs treated with, 408 

Carlier on parthenogenesis, 366 

Carpenter, F. B., cotton plants received from, 324 

Carpocapsa pomonella taken under burlaps, 171 

Castor oil on eggs, 417 

Catbird attacking the gypsy moth, 6,208,213 

destruction of silkworms by, 6 

feeding habits, 237 

Caterpillars of the gypsy moth attacked by Polistes pallipes, . . 378 

attacked by predaceous bugs 392 

attracted to light, 310 

become a serious nuisance, 14 

comparison of numbers of, destroyed annually, .... 93 

description of, 300 

destroyed by birds, 7, 96, 209, 228 

destruction of, by burning, .... 57, 58, 59, 87, 126, 165 

destruction of, by spraying, 58 

detrimental to real estate, 21 

disease among 280 

distance travelled by, 58, 310 

distributed by birds, 214, 236 

distributed by spraying, 113 

distribution of, 54,58,97,112 

effect of cold on, 96, 328 

effect of heat on 96, 327 

European methods for destroying, 117,284 

expense of destroying, 79 

feeding habits pf, 311 

feeding on cotton plant, 324 

first and last appearance of, 304 

food selection by, 485 

found on vehicles, 39 

indications of presence of, 86 

insecticides for destroying, 137, 417, 477 

killed by spraying, 57, 64 

length of life of the, 96, 306 

loss of weight in pupating, 333 

means of preventing spread of, 63 

molting of, 304, 308 

not affected by insecticides, 157, 474 

number from single egg-cluster, 94, 297 

number greatly reduced by exterminative methods, ... 60 

obstruct railroad trains in Europe, 280 

places of pupation, 335 

poisoned, analyses of, ......... 474 

prevented from ascending trees 64 

scattering of. See Distribution. 

spinning habits of , 102,330 

sprayed with contact insecticides, .... 57, 163, 485 
spread of, injury caused by, 59 



INDEX. 



lxvii 



been 



moth 



,214 



40, 1 



224, 



PAGE 

114 

170, 311 

169 

98, 325 

. 268 

2, 187, 188 

267 

. 392 

58 

122, 407 

. 208 

207, 219 

. 279 

227,231,236 

230, 237 



207, 215, 226, 227 
63, 125, 408 
. 481 
. 235 
. 405 
. 405 
379, 402 
. 244 



received, 



Caterpillars of the gypsy moth taken under burlaps, 

traps for, 

value of burlap against, 

vitality of, ..... 
Caucasus, The, occurrence of the gypsy moth in 
Cement, use of, on trees, 
Ceylon, occurrence of gypsy moth in, 
Chcetomyia crassiseta, .... 
Chelsea, outbreak of the gypsy moth in, 
Chemicals for killing eggs, . 

Chestnut-sided warbler attacking the gypsy moth, 
Chewink attacking the gypsy moth, . 
Chianti, ravages of the gypsy moth in, 
Chickadee, destruction of gypsy moth by, . 20S, 210 

feeding habits of, ..... 
China, North, occurrence of the gypsy moth in, 
Chipping sparrow attacking the gypsy moth, 
Chlorine used on eggs, 
Chloro naptholeum, experiments with, 
Chrysomela scalaris attacking elm trees, 

Chrysopa sp., 

Cicindcla 6-guttata, .... 
Cimbex americana, .... 
Circumstances favoring extermination, 
Cities and towns from which false alarms have 

beyond infested area, inspected, . 
Citizens, assistance of, in destroying the gypsy 

of Medford on escape of the gypsy moth, 
Clark, J. C, statement of, .... 

Cleaning knives, 

Clercy, J. O., on birds v. insects, 

Clifford, L. M., statement of, 

Climate, increase of the gypsy moth retarded by 

of England, influence on foliage, . 
Clisioeampa americana, 

destroyed by Baltimore oriole, 

parasites of, ..... 
Clisioeampa disstria, .... 
Coal tar, eggs treated with, 

use of, in pruning, 
Coeeyzus americanus. 1 ^ Cuckoo> 

erythrophthalmus. i 

Cocoon, formation of, ... 33 

Codling moth taken under burlaps, 

Cogswell, Hon. Wm. , resolution introduced into Congress by, . 

Colaptes auratus. See Flicker. 

Cold, effect of, on caterpillars, 

effect of, on eggs, 

Coleoptera, predaceous, . . . ' ■ 

Collinson, Mr., importation of the gypsy moth into England by, 



34, 



201 

198 

68, 77, 84 

4 

19, 24, 31 

126 

. 205 

24 

5 

. 271 

. 402 

. 213 



. 402 
. 410 
177, 186 



. 


171 




S3 


96, 


328 


294, 


295 


. 


381 


. 


269 



lxviii 



THE GYPSY MOTH. 



70 



infested re 



PAGE 

. 70, 80 

65, 70, 248 

85, 86, 107 

70 



Colonies of the gypsy moth, age of new, . 

exterminated, 

found in woodland, 

found outside of region infested in 1891, 

isolated, 

isolated, normal rate of increase in, 

isolated, spread of, 

means taken to find new, .... 

resulting from traffic 

Colony, definition of, . 
Colors of gypsy moth, explanation of, 
Colt, W. C, observations on the flicker, 
Commission appointed by Governor Brackett, . 
appointment of second, .... 
first, amount expended by, . 
Metropolitan Park, hold meeting with the gypsy moth commis 

sion, 

removal of first, . . . . 
report area of infested territory, . 
second, amount expended by the, . 
Commissions, consultation of first and second, . 
Commissioners, second, receive no remuneration, 
Committee, agricultural, hearing held by, . 
agricultural, Medford visited by, . 
on gypsy moth, appointment of, . 
entomological adviser appointed to, 
information concerning the gypsy moth in Europe obtained by 
members of, elected, ..... 

name of, changed, 

organization of, ...... 

plans of, presented to legislature, 

report of, on the inspection of towns bordering 

report of Professor Fernald and the director to 

work of, . 

Common names of the gypsy moth, . 
Comparative effects of different arsenical poisons, 
Comstock, Prof. J. H., infested region visited by, 

report of (Appendix E). 
Condition of infested region in 1891, . 

Conference at office of State Board of Agriculture (Appendix 
Congress, efforts to secure an appropriation from, 

resolve asking for aid sent to, . 
Connell, Mrs. Margaret, statement of, 
Consumption of food by gypsy moth caterpillars, 

Contact insecticides, 

Contopus virens. See Wood pewee. 
Cook, Prof. A. J., experiments with Paris green, 
Corea, gypsy moth from, ..... 
Cork oaks attacked by the gypsy moth, 
Corrosive sublimate, eggs treated with, 
Corvus americanus. See Crow. 



A), 



23 
315 

57, 58, 163, 485 



162 
338 
274 
409 



INDEX. 



lxix 



Cotton as a food plant, . 

trees banded with, 
Cotton, John, statement of, 
Coxe, Win., on tree pruning, 
Craig, W. C, at conference on gypsy moth 

statement of, .... 

Creepers attacking the gypsy moth in Europe, 

attracted by meat, 
Cremaster, use of, .... 
Creosote and paint tube, 

eggs treated with, .... 

for destroying caterpillars, . 
Cricket, destruction of crops by, 
Crimea, The, ravages of the gypsy moth in 
Crockford, A. W., statement of, . 
Cronin, Mrs. Margaret, statement of, 
Crow blackbird attacking the gypsy moth, 
Crowley, John, statement of, 
Crows attacking the gypsy moth, 

attacking the gypsy moth in Europe, 

attracted by meat, 

destroying predaceous insects, 

distributing the gypsy moth, 

experiments on gypsy moth eggs with, 

time required in digestion by, 

value of, 

Cuckoo as an insect destroyer, . 

attacking the gypsy moth, . 

attacking the gypsy moth in Europe, 
Currant sawfly, damage from, 
Curtis on occurrence of the gypsy moth in 
Cutting and burning infested growth, 
Cyanide of potash on eggs, . 
Cyanides as insecticides, 
Cyanocitta cristata. See Blue jay. 
Cyclone burner for destroying the gypsy moth, 

nozzle, 

nozzle used for burning, . . 
Cyrtoneura stabulans 



(Append 



ix A), 



63, 



27, 



6, 



207, 



211, 2 



England, 



39, 



PAGE 

. 324 

127, 128 

27, 44 

178 

45 

19, 27 

209 

229 

333 

124 

123, 410 

126 

206 

279 

30,42 

23 

207 

7, 18, 29 

207, 217, 224 

209 

. 229 

241, 394 

. 237 

. 239 

. 204 

. 204 

. 205 

12, 225, 227 

208, 211 

. 270 

269 

85, 164, 193 

. 413 

. 485 



121, 127 
. 150 
. 120 

387, 389 



D. 

Daly, D. W., statement of , . 
Damage by gypsy moth in Old World, 
Danger from bad pruning, 

from freight shipments 

from steady traffic, 
Dasyllis sacrator, . 
Datana ministra, . 
Date of hatching of the gypsy moth, 
Daudeville on ravages of gypsy moth in France 



9 
273 
173 
110 
109 
392 
402 
294 
276 



Ixx THE GYPSY MOTH. 

PAGE 

Davis, Miss R. L., observations on molting, 305 

De Courval on tree pruning, 178 

Defoliation of trees, 8-28, 85, 86, 273-284 

Dendrolene, description of, 135 

Dermestes (iter, 385 

lardarius, 384, 385 

Des Cars on tree pruning, 179, 186 

Destruction of birds, folly of, 205 

of caterpillars, 58,59,87,126,165 

of egg-clusters. See Egg cluster. 

of gypsy moth, methods for, 117 

of pupa? and moths, 194 

Destructiveness of the gypsy moth, . . . .23, 40, 57, 273-284 

of introduced insects, 250 

Dexter elm, the, 247 

Digestion of birds, 204 

of eggs of the gypsy moth by birds, 239 

Digestive system of gypsy moth, 369 

Diglochis omnivorus, .......... 375 

Dimorphism, sexual, of gypsy moth, 272 

Dill, J. P., statement of, 16,26 

Dionychopus niveus, 341 

Diptera, predaceous 392 

Dipterous parasites, 336, 376, 385 

how reared, 386 

Dei, Apelle, on ravages of gypsy moth in Europe, .... 2-79 
Director of field work, inspection of infested region by, ... 46 

visit to Washington by, 83 

recommendations of entomologists considered by, ... 69 

report of, to committee, 69 

visit to Amherst by, 46 

Description of different stages of the gypsy moth, . 288, 300, 333, 336 

of dipterous parasites, 387 

Disease among caterpillars, 280, 405 

Distance females can assemble males, 240, 351 

travelled by caterpillars 310 

Distribution of the gypsy moth, 94 

affected by extermination, 113 

affected by food supply, 95,97 

affected by natural causes, 97 

a study of methods and routes 106 

as caterpillars, .......... 98 

as eggs, 98, 103, 239 

by animals, 103 

by birds, 98,215,231,235,239 

by man, 99, 100, 103, 106, 278 

by traffic, 102-105, 109, 345 

by travelling of caterpillars, 310 

by wind 98, 278, 301 

compared with that of other insects, 97 

in other countries, 267 



INDEX, 



lxxi 



PAGE 

98, 99 
104 
104 
99 
107 
104 



Distribution of the gypsy moth, peculiarities of, 

period of greatest, 

primary, 

relation of population to, .... 

results of study of methods, 

secondary, ....... 

District infested by gypsy moth. (See Infested region. 

Dohrn, Dr., on parthenogenesis, 366 

on vitality of larvre, 278 

Donitz on singing Lepidopteron, 341 

Donovan on occurrence of gypsy moth in England, .... 268 

Douglass and Scott on breeding Heteroptera, 394 

Dowd, Mrs. John, statement of, 22 

Downy woodpecker attacking the gypsy moth, .... 207, 221 

Drassus sp. attacking the gypsy moth, 405 

Drew, C. R., statement of, ......... 59 

Dryobates pubescens. See Downy woodpecker. 
villosus. See Hairy woodpecker. 

Dryocampa rubicunda, 402 

Dubois on ravages of the gypsy moth in Belgium, .... 279 



E. 

Ebermayer, Dr., on birds v. the gypsy moth, 
Eck raupenleim machine, .... 
Effects, injurious, of arsenic (Appendix F), 

of extermination on distribution, 

of insecticides on foliage, 
Egg-clusters of the gypsy moth, advantage of destr 

age of, how determined, 

comparison of number destroyed annually, 

destruction of, 

destruction of, in Europe, 

distribution of, by streams, 

how laid, 

number of caterpillars from, 

number destroyed in 1891, 

of unfertilized females, 

old distinguished from new, 

size of, .... 

treated with acids, 

treated with creosote, . 

where found, . 
Egg-feeding birds, value of, 
Egg-gathering and fall inspection, 
Eggs of the gypsy moth, birds which may eat, 

burning of, 

danger from transportation of, 

description of, 

destruction of, 

distributed bv birds, 



uction of, 



. 209 

. 133 

161, 162 

. 113 

159, 489 

84, 117, 284 

95 

93 

63, 117 

. 284 

98 

. 363 

94, 297 

54 

290, 367 

95 

. 289 

63, 123, 413, 415 

63, 123, 410 

98, 126, 289 

. 229 

60 

228, 229 

57, 119, 284 

. Ill 

. 288 



35, 39, 53, 63, 69, 78, 84, 125, 195 
230, 239 



lxxii 



THE GYPSY MOTH. 



PAGE 

Eggs of the gypsy moth, effects of digestive processes of birds upon, 239 

effects of extremes of temperature on, 292 

experiments with insecticides on, 407 

hatching of, how accomplished, 297 

how covered, 289 

implements used in search for, 125 

number of, deposited, 94, 289 

number of, in female, 364 

number of, laid by poorly fed females, 95 

of dipterous parasites, 385 

removed by dissection, 364 

scattering of, 117,239,290,363 

time required for fertilization, 
vitality of, 

Eichoru raupenleim machine, 

Elachiptera dispar, .... 

Electric insecticide, .... 

Elm, the Dexter, 

trees attacked by Chrysomela scalaris 

Elms attacked by gypsy moth, . 

" Elphona," 

Embryo, development of, 

Emerging, process of, .... 

Emerton, J. H;, spiders identified by, . 

Empidonax minimus, .... 

Employees, number of, yearly, . 

uniform of, 

Emulsion, kerosene, use of, 

Enemies, natural. See Natural enemies. 

England, extermination of gypsy moth in, 
occurrence of gypsy moth in, 

English sparrow attacking the gypsy moth 
importation of, into America, 

Eutachina larvarum, .... 

Entomological adviser, Prof. C. H. Fernald appointed, 
opinion of, in regard to extermination, 

Entomologists, recommendations of, 
conference of, ... 
infested region inspected by, 
reports of (Appendices D and E) 
spraying recommended by, . 

Enwright, Win. J., statement of, 

Epeira strix, 

Epiblemum scenicum, . 

Escape of the gypsy moth, statements in regard to, 

Essex County Agricultural Society, petition presented by 

Eupelmus bifasciatus, ... 

Europe, distribution of gypsy moth in, 

methods of destroying the gypsy moth in, 1 

European bird 9 attacking gypsy moth eggs, 
birds, introduction of, . 



343 
279, 291 
131 
390 
482 
247 
235 
277 
483 
288, 294, 295 
336 
404 
207 
89-91 
114 
163, 485 

. 269 
267, 268 
208, 231, 234 
233, 234 
392 
57 
67 
69 
45 
69, 79 



17. 



45 

40 

405 

405 

4 

36 

377 

267 

284 

231 

232 



INDEX. lxxiii 

PAGE 

European dipterous parasites, 392 

food plants, 325 

hymenopterous parasites, 377 

methods for destroying the gypsy moth, ..... 284 

predaceous beetles, 385 

Eurytoma abrotani, .......... 377 

Everett, petition presented by selectmen of, 36 

Eversman, Professor, on ravages of gypsy moth in Orenboorg, . 280 
Examination of stomachs of various birds, . . . 212,215,231 

of stomach of toad, 405 

Excresences from bad pruning, 177 

Exhibit at Atlanta Exposition, 201 

at Mechanics Fair, 201 

at World's Columbian Exposition, 200 

Exorista sp., parasitic, on gypsy moth in America and Europe, . 387, 392 

Experiment station, 87, 406 

Experiments, amount of food consumed, . . . . . .315 

assembling, ........... 345 

birds v. gypsy moth eggs, 229 

cotton as a food plant, 324 

destruction of eggs 122 

distance travelled by caterpillars, 310 

effects of light on caterpillars, 310 

extremes of heat and cold on caterpillars, 327 

extremes of heat and cold on eggs 292 

fertilization of female moths, 343 

food plants, 316 

food selection, 485 

insecticide, 55, 69, 87, 407, 417, 477 

insecticides on foliage, 489 

parthenogenesis, .......... 365 

trapping caterpillars, 311 

trapping male moths, ......... 357 

Exterminated colonies, 70, 248 

Extermination, advice of State Board of Agriculture concerning, . 70 

aid given by birds, 238 

by burlapping and hand killing, 64 

circumstances favoring, ........ 244 

effect on distribution, 113 

how accomplished, 127 

in orchards, ........... 248 

in outer towns, 115 

in woodland 88, 248 

local success of, 247 

measures urged to provide for, 35 

obstacles to, 245 

opinions of entomologist in regard to, C7 

progress of, 244 

results of efforts toward, 70 

spraying not successful as a means of, .... 56, 62, 138 

Exterminative measures, numbers of caterpillars reduced by, . . 60 

External anatomy of moth, 339 



lxxvi 



THE GYPSY MOTH, 



Fowls feeding on gypsy moth caterpillars, . 

France, ravages of the gypsy moth in, 

Fraxinus excelsior, exempt from ravages of .gypsy moth, 

Freezing mixtures, 

French, J. N., statement of, 

Frisch, J. L., on injuries by gypsy moth, . 
Frost, H. L. , on food plants of the gypsy moth, 

on predaceous bugs, 

Fruit crop increased by spraying, .... 

loss of, ... 

poisoned by spraying, 

trees in Europe attacked by gypsy moth, 

trees how sprayed, 

Fiirst, Hermann, quoted on birds attacking caterpillars, 



PAGE 

. 222 
274-276, 283 
282 
293 
30, 31 
274 
316 
395 
60 
26, 41 
161 
271 
158 
208 



G. 

Galeruca xanthomelceiia, increase of, due to sparrows, 

Garden crops destroyed, 

Gases for destroying eggs, 

Gaurax anchora, ....... 

Gazen on ravages of gypsy moth in Kirsanov, . 

Genitalia, description of, 

Germany, ravages of the gypsy moth in, . 
Gerstiicker, Dr., on the killing of trees by gypsy moth 

Gibson, 11., statement of, 

Glands, accessory, of gypsy moth, 

Glass, binocular, use of 

Glover, Townend, on insectivorous birds, . 

Glucose, use of, 

Godart, on injuries by gypsy moth, 

Goodell, Pres. H. H., aid of, in securing assistants, 

letter to Governor-elect Brackett by, . 
Goodwin, F. M. , statement of, . 
Goodwin, J. O., description of movements of gypsy 
lars, 

statement of, 

Gordon, Miss Carrie, observations on molting, . 

Gould, L. S., at conference on gypsy moth (Appendix A) 

Gould pumps, 

Grackle, purple, attacking the gypsy moth, 

Grseser on distribution of gypsy moth, 

Graff, V. E., on ravages of gypsy moth in Riazan, 

Grafting wax, use of, in pruning trees, 

Grain attacked by gypsy moth in Europe, . 

Grass eaten by gypsy moth caterpillars, 

Great-crested flycatcher attacking gypsy moth caterpillars 

Great titmouse attacking other birds, . 

Green, I. C, observations on the redstart, . 

Green, Paris. See Paris green. 

Grimm on feeding habits of birds, 



moth oaterpil 



235 

26 

125 

387 

282 

339 

274 

277 

20 

375 

125 

207 

55, 142 

275 

4G 

35 

12, 19 



13 

21,31 

304 

45 
150 
207 
267 
281 
177 
283 
68, 282 
207 
233 
219 

208, 222 



INDEX. 



lxxvii 



7, 



Grosbeak, rose-breasted, attacking gypsy moth, 
Grote, Prof. A. R. , on systematic position of dispar, 

Gulls as insect destroyers 

Gypsy moth, acclimation of, ... 

act to provide against depredations by, 

annual increase of, .... 

area occupied by, 

attacked by parasites, .... 

attacked by predaceous insects, . 

bibliography of, 

caterpillars. See Caterpillars of the gypsy moth 

colonies of, exterminated, 

committee, appointment of, . 

committee, meeting of, with Metropolitan Park Commission, 

committee, name of, changed, 

comparison of numbers destroyed yearly, 

common names of, .... 

conditions favoring rapid increase of, . 

description of caterpillar, 

description of eggs, .... 

description of imago, .... 

description of pupa, .... 

destruction of, by birds, 

destruction of, by burlapping, 

destruction of, by burning, . 

destruction of, by spraying, . 

destructiveness of, .... 

distribution of. See Distribution. 

efforts of citizens to destroy, 

egg-clusters. See Egg-clusters. 

exterminative methods to reduce number of, 

female. See Female. 

first destructive appearance of, 

food plants of 

form in which imported 

hermaphrodites, 

hibernation of, 

history in America, 

history in the Old World, .... 

identification of, 

in America, occurrence of, recorded by Professor Riley, 

in England, 

in England, how exterminated, 

in Europe, 

in Europe, methods for destroying, 

increase of, checked, .... 

increase of, clue to English sparrow, . 

increase of, retarded by fires, 

increase of, retarded by isolation, 

injuries of, in Old World, 

injuries of, to woodland, 



PAGE 

207, 219 

256 

206 

94 

47 

95 

94, 103 

375, 385 

381, 392 

. 257 



65 
49 



76 

93 

256 

95 

300 

288 

336 

333 

96, 209, 272 

167 

19, 127 

58 

57, 70 



23, 40, 



34, 68, 



58, 



77, 84 

60 

7 
97, 318 
4 
339 
245 
3 
273 
32 
3 
268 
272 
67, 274 
284 
94 
235 
7 
6 
273 



lxxviii 



THE GYPSY MOTH. 



PAGE 

Gypsy moth, introduction of into America by Leopold Trouvelot, . 3 

introduction of, recorded by Professor Fernald, .... 3 

Japanese, size of, 338 

males. See Male moth. 

means of preventing spread of, caterpillars, .... 63 

means taken to find new colonies, 105 

migration of , in search of food, 13,97 

natural enemies of, 6, 95, 203, 375 

number of, colonies exterminated 70 

number of, destroyed by fire, 92 

number of, destroyed by spraying, 92 

number of eggs deposited by 94 

numbers of, in populated districts, ...... 99 

origin of isolated colonies, 103 

outbreak of, in 1889, 10 

parasites of 57, 96, 375, 385 

peculiarities of the distribution of , 98,99 

period of greatest distribution, 104 

plants destroyed by the, 70, 318 

possible spread of, 250 

pupa;. See Pupss. 

rapid development of, 86 

ratio of increase of, 95 

ravages of, first noticed, 32 

result of the transportation of, . . . . . . . 102 

seasons favorable for the increase of, 95, 96 

second brood of, 86, 295 

secondary distribution of, 104 

spread of, compared with that of canker worm, .... 97 
statements from citizens concerning escape of, ... . 4 

study of the distribution of, 94 

swarming of the male, 86 

systematic position of, 256 

v. English sparrow, 234 

weather favorable for the increase of, 84 



H. 



Hdbia ludoviciana, 

Habits, feeding, of gypsy moth caterpillars, 

of flight of gypsy moth, 

of the gypsy moth, observations on the, 

spinning, of gypsy moth caterpillars, . 
Hair deposited by the gypsy moth in laying, 
Hairs, aerostatic, of caterpillars, . 
Hairy caterpillars, immunity of, from birds, 

covering of nests, 

woodpecker attacking the gypsy moth, 
Hamlin, Mrs. I. W., statement of, 
Hand-killing of caterpillars, efficiency of, . 
Harlow, J. W., statement of, . 



207 

. 311 

. 344 

87 

279, 330, 332 
342, 364 
. 301 
208, 210 
. 289 
207, 221 
11, 20, 30 
64 
. 25, 28 



INDEX. 



Ixxix 



Harmon, Wm. B., statement of, . 
Harpalus caliginosus, .... 

pomsylvanicus, 
Harris, Dr. T. W., on occurrence of gypsy moth in E 
on use of burlap, ...... 

Hartiur, Dr. K., on raupenleim, .... 

on tree pruning, ...... 

infested region visited by, .... 

Harvey, Prof. F. L., report of (Appendix E). 
Hatch Experiment Station Bulletin, introduction of 

corded in, 

Hatching of gypsy moth caterpillars, date of, 

fall, 

Hauenstein raupenleim machine, 
Haushalter, F. H., statement of, . 
Haworth on occurrence of gypsy moth in England, 
Heat, effect of, on gypsy moth caterpillars, 
effect of, on gypsy moth eggs, 
fall hatching produced by, . 
Hermaphrodites, gypsy moth, 
Hemiptera, predaceous, 
Hemiteles fulvipes, .... 
Henry, Professor, on egg-killing, 

on ravages of the gypsy moth in France, 
Henshaw, Samuel, appointed entomologist to first commi 

on enemies of gypsy moth, .... 
Hericart, F., Viscount, on ravages of gypsy moth, 
Hess, Dr. Richard, on means of destroying the gyps 
Hibernation of the gypsy moth, . 

of parasites, ..... 
of predaceous bugs, 
Highways, caterpillars of gypsy moth found alon 

inspection of, .... 

History of gypsy moth in America, 

of gypsy moth in the Old World, 
Hochleim raupenleim machine, . 
Hofmann, Dr., on disease of nun moth, 
Holland, occurrence of gypsy moth in, 
Homeyer on distribution of gypsy moth, 
Hornets, predaceous, .... 
Hose, Eck raupenleim, 

for spraying 

House swallows driven away by sparrows, 
House wren attacking the gypsy moth, 
Howard, L. 0., opinions of, on gypsy moth wor 
Hutchins, John, statement of, 
Hyannis tobacco mixture as insecticide, 
Hydrochloric acid on eggs, . 
Hydrocyanic acid gas, eggs treated with, 
Hydrogen arsenide, eggs treated with, 
sulphide, eggs treated with, . 



k(- J 



land, 



PAGE 

26, 30, 41 
383. 385 
382, : U 
268 
171 
130 
180 
79 



ypsy moth re 



moth, 



pen 



dix E 



3 
294 
255 
133 
21 
268 
327 
19, 293 
296 
339 
392 
378 
118% 
283 
3S 
405 
276 
285 
245 
377 
403 
99 
197 
3 
273 
132 
405 

268, 283 
267 
378 
133 
147 
234 

208, 227 



43 
483 

413 

410 
412 
412 



lxxx 



THE GYPSY MOTH. 



PAGE 

Hylan, J. P., on assembling of gypsy moth, 345 

on leaf area of trees, 495 

Hyla pickeringii, 404 

Hymenoptera attacking the gypsy moth, 375 

Hymenopterous parasites destroyed by flycatchers, . . 220, 241, 376 

Hyphantria cunea, 402 

Hypogymna dispar, 255 



I. 



Ichneumon disparis, 

grandis, hibernation of, ... 

Ichneumons captured by birds, 

Icterus galbula. See Baltimore oriole. 
Imago of gypsy moth. See Female moth ; male moth. 
Implements used in searching for eggs, 
Importation of birds, .... 

of English sparrow, 

of gypsy moth, form of, 

of parasites, ..... 
Imported insects, damage from, . 
In-and-in breeding, .... 
Increase of the gypsy moth, 

conditions favoring rapid, . 

due in some measure to sparrows, 

influences that retarded, 

normal rate of, in isolated colonies, 

on neglected lands, 

ratio of, 

retarded by climate, 

retarded by isolation, 

weather favorable for the, 
Indigo bird attacking gypsy moth, 
Infestation, centres of, ... 

Infested estates, account kept of, 

localities, birds frequenting, 

localities designated on maps, 

region appointed to inspectors, . 

region, colonies found in 1891 outside of, 

region, condition in 1891, 

region, description of, . 

region, extent of, .... 

region, how inspected, . 

region, inspection of belt around, 

region of 1891, moth rarely found outside of, 

region, proportion of population in, 

region, railroads running through, 

region visited by Agricultural committee, 

region visited by entomologists, . 

towns, proportionate numbers of the gypsy moth in 



. 378 

. 377 

220, 241, 376 



125 
232 
233, 234 
4 

288, 406 

270 

368 

94 

95 

235 

5 

95 

31 

95 

5 

6 

84 

207, 219 

104 

52 

223 

50, 52 

49 

70 

53 

100, 101 

53, 108 

196 

108 

61 

101 

101 

36 

69, 79 

99 



INDEX. 



lxxxi 



Infested woodlands, .... 

woodlands, known area of, . 
Information, bulletin of, 

of the public, measures for, . 
Injuries by gypsy moth in Old World, 

severity of, 

spread of, 

to man and animals from spraying (Appendix F), 

to woodland by the gypsy moth, 
Ink, printers' used in destroying the gypsy moth, 
Insectary, description of , . 
Insecticides, contact, ..... 

danger from arsenical (Appendix F). 

experiments with, ..... 

for destroying caterpillars, . 
Insectivorous vertebrates (other than birds), 
Insect lime. See Raupenleim. 
Insects, birds as destroyers of, 

imported, danger from, 
Inspection, annual, 

force insufficient for, 

of belt around infested region, 

of Boston, result of, . 

of outside territory, 

of outside towns, result of, 

o*f railroads, . 

of wooded region, 
Inspections of 1891, 
Inspectors, observations reported by, 

town-sections allotted to, 
Internal anatomy of gypsy moth, 
Introduction of English sparrow, 

of European birds, 

of European parasites, . 

of gypsy moth into America by Leopold Trouvelot, 

of gypsy moth into England, 

of gypsy moth, recorded by Professor Fernald, 
Investigating committee, appointment of, urged by 

committee, 
Isolated colonies of the gypsy moth, 

injury from, .... 

normal rate of increase in, . 
Italy, ravages of the gypsy moth in, 



85 



Oi, 



PAGE 
. 116 

87 
34, 200 
34, 198, 200 
273 
58 
59 
. 161 
, 273-284 
34 
. 406 
58, 163, 485 



55, 69, 407, 477 
417, 477 
. 404 



204 

270 

196 

79, 81 

106 

80 

10, 111 

65, 70 
111 

66, 87 
60, 99 

51 

50 

368 

33, 234 

232 

288, 406 

3 

269 

3 



52 



;ypsy 



moth 



!, 77 

103 

95 

95 

279 



J. 



Jager, Dr., on diseases of nun moth, 
Japan, occurrence of gypsy moth in, 
Japanese gypsy moth, size of, 
Jay, blue, attacking the gypsy moth, 
attracted by meat, . 



. 405 
. 267 
. 338 
6, 207, 225 
. 229 



lxxxii 



THE GYPSY MOTH. 



Jay, blue, destroying predaceous insects, . 
distributing the gypsy moth, 

feeding habits of, 

Joly, M. N., on ravages of the gypsy moth, 

Jones, F. H., preparation of soap powder emulsion by. 



PAGE 

. 241 

. 236 
210, 231 
. 276 
. 163 



K. 



Kazan, ravages of the gypsy moth in, 
Kearly, George, on increase of insects following 
birds, 

on scarcity of gypsy moth in England, 
Kelly, Mrs. Daniel, statement of, 
Keppen, Theodore, note on cuckoo, 

on gypsy moth in Russia, 
Kerosene emulsion, use of, . 

for destroying caterpillars, . 

for destroying eggs, 
Kharkov, ravages of gypsy moth in, 
Kiev, ravages of the gypsy moth in, 
King birds attacking the gypsy moth, 
Kinglet attracted by meat, .... 
Kirby, Catalogue Lepidoptera Heterocera, 
Kirklaud, A. H., cages for breeding beetles, 

observations on wood pewee, 

on assembling of gypsy moth, 

on fall hatching 

on food selection by larvae, . 

on garden-toad, 

on internal anatomy of gypsy moth, 

on predaceous Hemiptera, 

on leaf area of trees, .... 
Kirsanov, ravages of gypsy moth in, . 
Kisheuev, ravages of gypsy moth in, . 
Klausen, experiments of, with wadding bands, 

Knapsack pump, 

Knives, cleaning, 

Kollar, Vincent, on egg killing, . 

on use of burlap, 

Kornauth, Wachtl and, on diseases of nun moth, 
Kulagiu, N., on injuries of gypsy moth in Russia, 



destr 



281, 283 
uction of 

. 205 

269 

22 

. 208 

268, 280 

103, 485 

126 

416 



281 
281 

207, 226, 227 
229 
255 
38-1 
220 
345 
296 
485 
404 
368 
392 
494 
282 
280 
286 
149 
126 
118 
171 
405 
280 



L. 

Labodsky on bands for trees, 

Lacy, Sylvester, statement of, 

Larches attacked by gypsy moth, 

Larch saw-fly, damage from, 

Laria dispar, .... 

Larvae of gypsy moth. See Caterpillars of 



285 
17 
277 
270 
255 



?yP s v moth. 



INDEX. 



lxxxiii 



Law for protection of birds, need of enforcement of, 
Lawrence, Gen. S. C, testimony of, . 
Lawrence, Mrs. C. A., statement of, . 
Lead, arsenate of. See Arsenate of lead. 
Leaf area of trees, .... 
Least flycatcher attacking the gypsy moth, 
Leaves, how injured by arsenical poisons, 
Legislature, petition for extermination of gypsy 
Length of life of imago, 

larvse without food, 
Lepidoptera attacked by predaceous bugs, 
Lepidopteron, singing, 
Lettuce, quantity eaten by gypsy moth, 
Lexington, area of woodland infested in, 
Light, caterpillars attracted to, . 
Limbs, large, removal of, . 
Lime, insect. See Itaupenleim. 
Limenitis Ursula, ..... 
Lindens attacked by gypsy moth, 
Lines of travel, relation of distribution to, 
Lintner, Dr. J. A., infested region visited by, 

report of (Appendix D), 
Liparis dispar, ..... 
monacha, damage by, 

use of raupenleim against, 
Literature on gypsy moth, . 
Lithobius forficatxts, .... 
Livonia, occurrence of gypsy moth in, 
Local extermination, success of, 
Localities, infested, birds frequenting, 
Locusts destroyed by birds, 
Lodi on vitality of caterpillars, . 
Loeffler, E., statement of, . 

London purple, 

Leech, J. H., on Japanese gypsy moth, 
Lycosa sp. attacking the gypsy moth, 
Lijmantria monacha, aerostatic hairs of, 

disease of, 



moth presented 



PAGE 

242 
10 
29 

. 494 

. 207 

. 494 

to, 36 

343, 362 

278, 325 

393 

341 

315 

87 

310 

184 

402 

274 

108 

69 



255 

130 

132 

257-267 

405 

267, 268 

247 

223 

205 

327 

42 

140, 417, 477 
338 
405 
301 
405 



M. 

Macharcea serriventris, .......... 392 

Machines for burning eggs, 119 

raupenleim, ........... 131 

spraying, 149-156 

Majorca, island of, occurrence of g3 r P s Y moth in 267 

Maiden, office removed to, 55 

petition presented by city officials of, ...... 36 

trees defoliated by gypsy moth in, 57 

Male gypsy moth, anatomy of, 339 

i attracted by pupa?, 363 



lxxxiv 



THE GYPSY MOTH. 



Male gypsy moth, birds feeding on, 
description of, 
digestive system of, 
distance over which female attracts, 
experiments in trapping, 
flight of, 

length of life of, . 
mating of, 
polygamous, . 
presence of fat in, . 
reproductive system of, 
Malpighian vessels of gypsy moth, structure of 
Man, distribution of the gypsy moth by, . 

Maps, section, 

Market gardeners, distribution of moth by, 

Marptusa familiaris 

Martin, Dr. Pearl, appointed commissioner, 

Martins driven away by sparrows, 

Maryland yellow-throated warbler attacking the gypsy moth, 

Massachusetts Agricultural College, students of, as assistants 

Horticultural Society, action of, . 
Mating of gypsy moth, 
Maynard, C. J., note on bird digestion, 
Maynard, Prof. S. T., recommendation concerning paintin 
Mayo, Mrs. Thomas F., statement of, 
McCarty, Miss R. A., statement of, . 

McGowen nozzle, 

McKee, George W., bark shave invented by, 
McLaughlin, Wm., statement of, 
Medford, brick shipments from, .... 
centre of infestation, ..... 
colonies of gypsy moth discovered in woods of, 
description of section 8 (Appendix C). 
distribution of caterpillars from, . 
gypsy moth fought by municipal authorities of, 
measures taken to destroy the pest in, . 
" Mercury," description by J. O. Goodwin of 
caterpillars in, ..... 

residence of Trouvelot in 

selectmen of, petition for extermination of g 

sented to Legislature by, 
statement of citizens as to escape of gypsy moth 
trees defoliated by gypsy moth in, 
woodland burned in, . 
Meeting of Board of Agriculture, special, 

opponents to spraying, . 
Meigenia bisignata, .... 
Melrose, outbreak of the gypsy moth in, 
Men, examination and training of, 

largest force of , . 
Menecles insertus, ..... 



ypsy 



g trees, 



movements of 



moth 



PAGE 

2-28-240 
. 336 
. 371 
240, 351 
69, 357 
344, 345 
343 
342 
343 
373 
373 
370 
99, 100-103 
50 
109 
405 
38 
234 
208 
46 
36 
342 
204 
178 
22, 24 
19, 25 
152 
190 
44 
110 
99 
85 

112 
33 
34 



15 



pre 



13 
4 

36 
4 

57 
166 

49 

56 
392 

58 
68, 85 

85 
393 



INDEX. 



lxxxv 



in the, 



Mephitis mephitica, 

Method of pruning, 

of rearing predaceous insects, .... 

of testing insecticides, ...... 

pursued in outside inspecting, .... 
Methods for destroying the gypsy moth, 

in Europe, 

most useful to the farmer, ..... 

Metropolitan Park Commission, gypsy moth committee 

ing With, ........ 

location of territory controlled by the, 

reservation, moths found in the, .... 

" Mercury," Medford, description of movements of caterp 
Merrill, Mrs. E. E , statement of, ... . 

Iferula migratoria, ....... 

Mesochorus, species parasitic on gypsy moth in Europe, 
Microgaster species, parasitic, on gypsy moth in Europe, 

value of certain species in Europe, 
Micropyle, description of, . 
Middlesex Fells, colonies of gypsy moth found 

condition of, . 
Migration of the gypsy moth in search of food, 
Milk inspectors, information furnished by, 

peddlers, distribution of gypsy moth by, 
Miller, J. C, statement of, . 
Minott, C. W., experiments by, . 

observations on feeding habits, 

observations on vitality of larvae, 

observations on creosote oil, 
Mirror, use of, ... . 
Mites attacking eggs, . 
Mixter, C. S-, statement of, 
Molting of the gypsy moth, 
Molts of gypsy moth larvae, 

time between, 
Mongoose, importation into Jamaica, 
Monteiro, Dr. A. A. C, on egg-killing, 
Morton, Hon. J. Sterling, matter of appropriation pr 
Moscow, occurrence of gypsy moth in, 
Mosher, F. H , experiments by, . 

observations on blue-jay, 

observations on ci'ow, . 

observations on cuckoo, 

observations on flight of female, 

observations on hairy woodpecker 

observations on tree frog, 

observations on vitality of larvae, 
Moth, gypsy. See Gypsy moth. 

gypsy, female. See Female gypsy moth 

gypsy, male. See Male gypsy moth. 

traps 



hold 



PAGE 

404 
177 
384, 394 
418 
60 
164 
284 
194 



meet- 



illari 



in, 



esented to, 



78 

78 

86 

13 

42 

216 

378 

377 

288 

289 

86 

87 

97 

107 

109 

13, 42 

418 

311 

299 

416 

125 

404 

41 

308 

304 

305 

233 

118 

83 

268, 283 

418 

214 

217 

212 

344 

221 

404 

299 



358, 360 



lxxxvi 



THE GYPSY MOTH. 



PAGE 

Moth, tussock, increase due to sparrows, 235 

Moulton, F. C, analyses by, 474 

experiments by, 142, 407 

on cyanides, 485 

Myiarchus crinitus, 207 



N". 



Names of gypsy moth, .... 

Naphtha burner for destroying caterpillars, 
Nason, Prof. F. L., inventor of dendrolene, 
Nasonov, Dr. N., on egg-killing, 

on methods of destroying the gypsy moth, 

on ravages of gypsy moth in Poland, . 
Native birds driven away by sparrows, 
Natural enemies of gypsy moth, 

birds, 

Coleoptera, . 

Diptera, 

Hemiptera, 

Hymenoptera, 

spiders, . 

vertebrates, . 

selection, effect on gypsy moth in England, 

selection, influence on colors of gypsy moth, 

selection, influence on flight of males, . 
Neitner, gypsy moth found in Ceylon by, . 
Nematus erichsonii, damage from, 

ribesii, damage from, .... 
Nervous system of gypsy moth, .... 
Neville, T. J., statement of, .... 
Nicholson, C., on extermination of the gypsy moth in En 
Nitric acid for destroying eggs, . 
Nitrogen dioxide for destroying eggs, 
Noctua-c-nigrum, ..... 
Nolken on distribution of gypsy moth, 
Norcross, J. Henry, efforts of, to secure an appropriation 
Nolhrus sp. attacking gypsy moth, 
Nozzle, cyclone, for burning, .... 

gem, used for contact insecticides, 
Nozzles for spraying, ...... 

Number of caterpillars from single egg-clusters, 
Nun moth, aerostatic hairs of, .... 

damage by (see Lymantria (Liparis) monacha), 
Nursery stock, where shipped, .... 
Nuthatch attracted by meat, .... 

feeding habits of, 

white-breasted, attacking the gypsy moth, . 
Nymjihcea odorata, 



land 



li; 



255, 256 
122, 126 
135 
118 
.284 
283 
234 
95, i)6 
203 
381 
385 
392 
375 
404 
404 
273 
272 
345 
267 
270 
270 
373 
23 
270 
123 
413 
400-402 
268 
36 
404 
120 
163 
49, 150, 154 
297 
301 
130 
108 
229 
231 
208 
317 



INDEX. 



lxxxvii 



O. 



Oak attacked by gypsy moth in Europe, 

leaf, area of, 

Obstacles to extermination, 
Ochsenheimer, " Schmett. v. Europa," 
Ocneria clispar, . . . 

act to provide against depredations by, 

See Gypsy moth. 
Ocneria rubea, peculiar structure on fore wings of, 

studies on, 

Odoriferous glands of bugs, 

Oil, creosote, for destroying eggs, 

hose, 

paraffine gas, used for burning, 

parafline gas, used on eggs, . 

rape, with tar for banding trees, . 

spray, burning with, .... 
Old World, injuries of gypsy moth in, 
Orchards attacked by gypsy moth, 

extermination of moth in, . 
Orenboorg, ravages of gypsy moth at, 
Organization of committee, 

of field force, 

of second commission, . 
Orgyia definita, influence of environment on, 
leucostigma, 

compared with gypsy moth, . 

destroyed by spraying, .... 

increase due to English sparrows, 
Oriole, Baltimore, attacking the gypsy moth, 
Osborn, Prof. Herbert, identification of mites, 
Outbreaks of the gypsy moth checked by birds, 

of the gypsy moth in 1889, . 
Oven bird attacking the gypsy moth, . 
Oviposition of gypsy moth, 
Ovipositor of gypsy moth, . 



6, 



TAGE 

274-277, 281-283 
495 
245 
255 
255 
47 



342 
256 
394 
03, 123, 410 
120 
120 
417 
285 

59 
273 
274 
248 
280 
38, 49 

50 

45 
273 
402 
272 
140 
235 
227, 237 
404 
205 

10 

208, 219 

363 

342 



213, 2 



P. 



Packard, Dr. A. S., infested region visited by, 69 

report of (Appendix D). 

Paint and creosote tube, 124 

for use in marking trees, 51, 124 

for use on wounds on trees, 178 

town section bounds marked with 50 

Palsacrita vernata, 402 

food plants of the, 97 

Palpi, labial, used in spinning, 332 

of imago, 339 



lxxxviii 



THE GYPSY MOTH. 



Panzer on ravages of gypsy moth, 
Paraffine gas oil for burning, 

gas oil on eggs, 
Parasitized pupa?, per cent, of, 
Parasites of gypsy moth, 

aid given by, in Europe, 

breeding, on many hosts, 

destroyed by birds 220. 

dipterous, 

hymenopterous, 

importation of, 

on eggs, 

vegetable, 
Parexorista sussurans, . 
Paris green, 39, 56, 58, 59, 80, 137, 138, 417 

analyses of, . 
Paris green and lime, analyses of 

comparative effects of, . 

experiments with, . 

on foliage, 
Parasitigena segregata, 
Park, Franklin, Boston, colony of gypsy moths found in, 

reservation, Metropolitan, moths found in, 
Parks, possible danger to, . 
Parthenogenesis, .... 
Parns atricapillus. See Chickadee. 

major, .... 

Passerina cyanea, .... 
Pearce, W. J., on parthenogenesis, 
Peddlers, routes of , 

Pedestrians, distribution of the gypsy moth by, 
Pekin, gypsy moth occurring at, 
Penza, ravages of the gypsy moth in, 
Pergande, Theo., identification of ants by, 
Perillus circumcinctus, .... 
Perkins, Dr. G. H., infested region visited by, 

report of (Appendix E), 
Perry, A. P., statement of, . 
Pesomachus hortensis, . 
Petition by city officials of Maiden, 

by city officials of Somerville, 

by Essex County Agricultural Society, 

by executive committee of the State Board of Agriculture, 

by Massachusetts Horticultural Society, 

by selectmen of Arlington, . 

by selectmen of Everett, 

by selectmen of Stoneham, . 

by selectmen of Wakefield, . 

by selectmen of Winchester, 

by State Board of Agriculture, 
Petroleum, use of, on eggs, 



PAGE 

275 

120 

417 

336 

375 

284 

377 

241, 376 

385 

375 

406 

63 

405 

392 

419, 473 

492 

492 

473 

436 

491 

392 

70 

86 

87 

365 

233 
207 
367 
108 
103 
268 
281 
381 
393 
79 

21 

378 

36 

36 

36 

36, 78 

36 

36 

36 

36 

36 

36 

36 

119, 288 



INDEX. lxxxix 

PAGE 

Pewee, wood, attacking the gypsy moth, 207, 227 

destroying parasites, 220, 376 

Phalcena (Bombyx) dispar, 255 

Phalangium dorsatum, .......... 404 

Phenol on eggs, 123, 414 

Phidippus galathea, 405 

Phidippus tripunctatus, 404 

Phlceothrips, 404 

Phoebe attacking the gypsy moth, 207, 227 

Phora incisuralis, ........... 387 

scalaris 387 

setacea 391 

Phorocera, 387 

Phorocera concinnata, 392 

Phosphoric acid deposits in caterpillar, 370 

Pierce, G. T., statement of, 41 

Pierce, Richard, statement of, 21, 29, 43 

Pierce, W. A., &\ conference on gypsy moth (Appendix A), . 45 

Pieris rapes, damage from, ......... 270 

Pimpla flavicans, ........... 378 

instigator, 378 

pedalis, 375, 377 

tenuicomis, .......... 375 

Pines attacked by the gypsy moth, 86, 277 

attacked by the gypsy moth in Europe, ..... 282 
Pipilo erythrophthalmus, ......... 207 

Piranga erythromelas, 207 

Pitch, trees banded with, 285 

Plants attacked by the gypsy moth, . . . .58, 70, 316, 318, 323 

in Europe, 325 

not attacked by the gypsy moth, 323 

Plaster of Paris, use of, on trees, 188 

Platynus limbatus, 384 

Plummer, Mrs. A. H., statement of, 29, 31, 42 

Podisus cynicus, ........... 392 

serieventris, .......... 393 

early stages of, 396 

Poisoned larva?, analyses of, 474 

Poland, ravages of the gypsy moth in forests of, .... 283 

Police regulations, enforcement of, 54, 55 

Polistes pallipes, 378 

Poltava, ravages of the gypsy moth in, ..... 281 

Polygamy of the gypsy moth, 343 

Pomerania, insect outbreak in, 205 

Pontederia cordata, 317 

Population of Massachusetts, proportion of, in infested region, . 101 

relation of, to distribution, 99 

Porchinsky, Dr. J., on means of distributing the gypsy moth, . . 286 

on ravages of the gypsy moth in the Crimea 279 

Porthetria dispar, 255 

systematic position of (see Gypsy moth), 256 



xc THE GYPSY MOTH. 

PAGE 

Post offices, frames placed in, 199 

Potassic cyanide on eggs, 413 

Potato beetle killed by arsenate of lead, 144 

Pratt, Augustus, elected a member of the committee, ... 76 

Predaceous Coleoptera, 381 

Diptera, 392 

Hemiptera, 392 

Hemiptera attacked by crows, ... ... 394 

Hemiptera, how reared, 394 

Hymenoptera, 378 

insects, aid given by, 284 

insects destroyed by birds 241 

insects, Dr. Altum on importation of 288 

Press, State, assistance given by, ....... 199 

Primary distribution of the gypsy moth 104 

Printers' ink used in protecting trees from gypsy moth, ... 34 

Process of emerging, 336 

of molting, t 308 

of pupation, 332 

Progress of extermination, ......... 244 

Protection of birds, law for, 206, 242 

Protoparce celeus, granules in, . . . . . . . . 370 

Pruning, effects of improper, 175 

infested trees, 172 

season for, 179 

Preyssler, on ravages of the gypsy moth, 275 

Pteromalus boucheanus, . . ....... 377 

halidayanus, . . . . . . . . 377 

pini, 377 

Ptinus brunneus, ........... 385 

Pumps, Gould, 150 

how repaired, 156 

knapsack, 149 

Pupae of the gypsy moth, arsenic found in, 476 

assembling by, 363 

attacked by parasites 376 

birds feeding on, 7, 208 A 228 

comparison of number of, destroyed annually, .... 93 

description of, 333 

destruction of, 58, 59, 194 

emerging of imago from, ........ 336 

parasites reared on, ......... 386 

per cent, parasitized, 336 

size of, 333 

time spent in, 333 

Pupation in the field, 335 

process of, 332 

Purple grackle attacking the gypsy moth, ...... 207 

Pyroligneous acid on eggs, 416 

Pyrophila pyramidoides, ......... 402 

Pyrrharctia Isabella, 377 



INDEX. 



xci 



Q. 



Quercus pedunculata attacked by gypsy moth, 282 

rubra, leaf area of, ......... 495 

Quiscalus quiscula, .......... 207 



R. 



Eailroad sidings, inspection of , . 

trains obstructed by gypsy moth, . 
Railroads running through the infested district, 
Bana silvatica, ...... 

Ransom, Miss M. M., statement of, . 
Ratzeburg on ravages of the gypsy moth, . 
Raupenleim bands, 

composition of, 

on eggs, .... 

trees banded with, 
Ravages of the gypsy moth in Massachusetts, 

of the gypsy moth in Old World, . 
Rawson, W. W., appointed commissioner, . 
Reaumer on birds destroying the gypsy moth, 
Red-eyed vireo attacking gypsy moth, 
Redstart, American, attacking the gypsy moth, 
Reduction of infested area, .... 
Region, infested. See Infested region. 
Regulations concerning the gypsy moth (Appendix B). 
Reid, H. N., experiments by, .... 

on trapping males, ..... 
Reply of State Board to order of Representative W 
Reports of inspectors, 

of State Board of Agriculture, extracts from, 

of visiting entomologists (Appendix E), 
Reproductive powers of gypsy moth, . 

system of gypsy moth, . 
Respiratory system of gypsy moth, 
Restriction of distribution of gypsy moth, 
Retractile tubercles of gypsy moth larva, 

secretion from, .... 
Bhynchagrotis alternata, 
Riazan, ravages of gypsy moth in, 
Richardson, D. M., statement of, 
Riegel, on ravages of gypsy moth, 
Riley, Prof. C. V., at conference on gypsy 

infested district visited by, . 

on assembling in the bombycidae, 

on insectivorous birds, . 

on occurrence of gypsy moth in America, . 
Rimrod, C. J., on ravages of gypsy moth, . 
Ritzema-Boz, Dr. J., on gypsy moth in Holland, 
Road commissioners of Medford, meeting of, . 



Ill 
. 280 
101, 102 
. 404 
20, 27, 29 
. 277 
129-135 
135 

125, 284, 285, 417 
64, 69, 136 
. 7-44 
. 273 
38 
232 
207, 216 
208, 219, 227 
. 245 



J. D. Bullock 



65-67, 78 



moth (Appendix A), 



418 

357 

73 

51, 52 
81, 82 



245 
373 
372 

114 

302 

304 

400, 402 

281 

12, 27 

277 

45 

56 

357 

207 

3 

275 

283 

33 



268 



XC11 



THE GYPSY MOTH. 



PAGE 

Roads, destruction of eggs along, 63 

isolated colonies found along the, 54 

Robert, M., on tree scraping, 191 

Robin, American, attacking the gypsy moth, . . . 208, 216, 227 

destroying predaceous insects, 241 

destruction of silk worms by, 6 

experiments on, 204 

Rogers, J. H., statement of, 17 

Romanoff on distribution of gypsy moth, 268 

Rose-breasted grosbeak attacking the gypsy moth, . . . 207, 219 

Routes of transportation, study of the 106 

Rowe, C. H., on predaceous beetles, 381, 382, 385 

Rubbish, destruction of, 193 

Rudzky, on egg destruction, 285 

Rules and regulations concerning the gypsy moth (Appendix B), 

Russell, G. C, statement of, 21 

Russell, Gov. Wm. E., removal of salaried commission by, . . 45 

Russell, Mrs. E. M., statement of, 21 

Russia, occurrence of gypsy moth in, 268 

ravages of gypsy moth in, 279, 280 

Ryder, Mrs. P. N., statement of, 43 



s. 

Salisbury on occurrence of gypsy moth in England, 

Samara, ravages of gypsy moth in, . 

Samuels, E. A., record of destruction of silkworms by birds, 

on value of birds, .... 
Sanderson, L. B., notes on wood thrush, 

statement of, .... 
Sap, circulation of, in trees, 
Saratov, ravages of gypsy moth in, 
Sarcophaga, parasitic, .... 
Sarcophaga affinis, .... 
Sargent, Dr. C. S., translation of Des Cars' " Tree Pruning 
Sargent, F. W., elected member of the committee, 
Saugus, gypsy moth found in, 
Saxony, ravages of gypsy moth in, 
Sayornis phoebe. See Phoebe. 
Scales of gypsy moth wings, form of, 
Scarlet tanager attacking the gypsy moth, 
Scattered eggs, 

eggs, fertility of, .... 
Scattering of caterpillars, . 
Schseffer, J. C, on ravages of gypsy moth 
Scheffer, M., on use of burlap, 
Scheuerlen, Dr., on disease of nun moth, 
Schmidberger on egg-killing, 
Schrader, F. C, experiments by, 
Schrank " Fauna Boica," 
Scolytidre, attacking trees, . 



in Saxony 



by 



268 

281 

6 

205 

236 

59 

175 

281, 282 

387, 389 

. 392 

179 

76 

53, 86, 87 

. 274 

341, 342 

207, 227 

63, 117, 363 

. 239 

. 114 

. 274 

171 

. 405 

. 117 

360, 418 

. 255 

. 190 



INDEX. 



xcm 



Scolytns destructor attacking trees in England, . 
Scraping of eggs from trees, method of, discarded, . 

of eggs from trees, recommended by Europeans, 

of trees, 

of trees, value of, ........ 

Scudder, Samuel, at conference on gypsy moth (Appendix A), 
Season for pruning, 

larval, distribution in, ...... 

Second brood of the gypsy moth, ..... 

" Section " books, record of infested estates kept in, 
Section 8, Medford, description of (Appendix C). 
Sections, towns divided into, ...... 

Seitz, raupenleim machine, 

Seopru, Georg, on ravages of gypsy moth in the Crimea, . 
Sessions, Hon. Wm. K., appointed member of committee, 

at conference on gypsy moth (Appendix A) 

chosen chairman of committee, 

Medford visited by, .... 

member of committee sent to Washington, 
Sex differentiation in larvae, 
Sexual dimorphism of gypsy moth, 

Shade trees, how sprayed 

Shaler, Prof. N. S., appointed member of committee 

assistance given by, .... 

at conference on gypsy moth (Appendix A) 

interview with Mr. Trouvelot, 

resignation of, 

Shaw, II. J., moth trap invented by, . 

observations on red-eyed vireo, . 
Shellac, use of, in pruning, .... 
Sherman, J., statement of, .... 
Sherman, Walter, statement of, . 
Shipov, ravages of gypsy moth in, 
Sialia sialis. See Blue bird. 
Siberia, occurrence of the gypsy moth in, . 
Sidings, railroad, inspection of, . 
Siebold on parthenogenesis, 
Silk, amount spun by gypsy moth caterpillars, 

glands of caterpillars, .... 
Silkworms destroyed by birds, . 

Silpha quadripunctata, 

Simbeersk, ravages of gypsy moth in, 
Sinea diadema, ...... 

Size of imago, variation in, . 

Skunk attacking the gypsy moth, 

Smith, Prof. J. B., infested region visited by, 

on insectivorous birds, .... 

on raupenlein, 

on systematic position of dispar, . 

report of (Appendix D). 
Smith, J. W., data furnished by, concerning wind 



PAGE 

192 

63 

292 

189 

172 

45 

179 

110 

86, 295 

52 



49 

133 

280 

49, 76 

49 
34 

83 

374 

272 

158 

49 

72 

45 

4 

72 

360 

221 

177 

20 

20, 26 

282 



267, 268, 280 
111 



366 

331 

370 

6 

287 

281, 283 

405 

338 

404 

69 

207 

135 

256 

350 



xciv THE GYPSY MOTH. 

PAGE 

Snowdon, W. H., statement of 13,18,25,30 

Soap powders, use of, as contact insecticide, .... 163, 485 

Soda, arsenate of, experiments with, ....... 143 

Somerville, petition presented by city officials of , .... 36 

Sorauer, Dr. Paul, on tree pruning, 181 

South, Richard, on extermination of gypsy moth in England, . . 269 

Spain, occurrence of gypsy moth in, 268 

Sparrow, chipping, feeding on gypsy moth caterpillars, 207, 215, 226, 227 

English, attacking the gypsy moth, 208 

English, feeding on gypsy moth eggs, 231,239 

English, introduction of, 233, 234 

Sparrows feeding on gypsy moth, . .... 219, 228 

Speyer on distribution of gypsy moth, 267 

Sphinx drupiferarum, .......... 383 

Spiders attacking gypsy moth, 404, 405 

" Spiegel," destruction of, 284 

Spines on wings of gypsy moth, 341 

Spinney, Mrs. F. T., statement of, 12,18,29,32 

Spinning habits of caterpillars, 102, 278, 330, 332 

Spiny area on wings, 341 

1 Spizella socialis, .......... 207, 215 

Spray, burning with oil, 59 

Spraying against gypsy moth, 157 

apparatus, 145-156 

benefit to fruit crops from, '. . 60 

burlapping substituted for, 64 

caterpillars distributed by, 113 

caterpillars killed by 57, 58, 64 

danger from (Appendix F), 

distribution lessened by, 64 

poisons for use in, 55, 417, 477 

not effectual as an exterminative method, 56 

number of moths destroyed by, 92 

prejudices against, 118, 199 

recommended by entomologists (Appendix A), . . . .45,55 
rules concerning (Appendix B). 

system of, 56 

time of, 156, 157 

with arsenate of lead, 87 

with arsenate of lead, effectiveness of, 80 

with arsenical insecticides, failure of, as a means of extermina- 
tion, 62 

with contact insecticides, 57 

with Paris green. See Paris green. 

with Paris green, opposition to, 56 

outfits, 55, 140 

Spread of gypsy moth, comparison with that of canker worm, . 97 
efforts to prevent the, ......... 79 

in twenty years, 5 

in woods, ........... 115 

slow, ............ 245 



INDEX. 



xcv 



ypsy 



committee 



87, 406 
267 
405 
255 
269 



moth 



PAGE 

Squirrels, eggs scattered by, 231 

Starling attacking nun moth in Europe, ..... 208, 209 
State Board of Agriculture. See Board of Agriculture. 
Statements of citizens concerning the gypsy moth (Appendix G), 7, 8-10, 

11-13, 14-32, 33, 40-44, 59 
Station, experiment, erection of, ... 

Staudinger on distribution of gypsy moth, . 

Steatoda borealis, 

Stephens, " Illustrations of British Entomology," 

on occurrence of gypsy moth in England, . 
Stephenson, Dr. F. B., translation of Russian works 

by, 

Stetson, John, statement of, .... 

Stetson, S. S., elected a member of the gypsy moth 
Stockholm, occurrence of gypsy moth at, . 
Stomach examination of cuckoo, 

examination of toad, ..... 

of gypsy moth larva, 

Stoneham, petition presented by selectmen of, . 

Stone walls, comparison of yearly work on, 

St. Petersburg, non-occurrence of gypsy moth at, 

Streams, caterpillars distributed by, . 

Studies on systematic position of dispar, . 

Study of the methods and routes of transportation, 

Sulpho-naphthol, ....... 

Sulphur dioxide on eggs, 

Summer pruning, 

Swallows, house, driven away by sparrows, 
Swampscott, outbreak of the gypsy moth in, 
Sweden, occurrence of gypsy moth in, 
Swill-takers, distribution of the moth by, . 
Swinton on sound producing insects, . 
Syrphus sp. attacking the gypsy moth, 
Systematic position of dispar 



268 

10 

84 

267 

212 

405 

369 

36 

93 

268 

98 

256 

106 

484 

416 

184 

234 

58 

267 

109 

341 

405 

256 



T. 



Tachina, European parasites of gypsy moth, 
Tachinids captured by birds, 

parasitic, ..... 
Tambov, ravages of the gypsy moth in, 
Tanager, scarlet, attacking the gypsy moth 
Tangl, Dr., on disease of nun moth, 
Tar and rape oil bands, 

bands, 

coal, use of, in tree pruning, 

used on eggs, 
Tarred burlap, use of, on trees, . 

paper, trees banded with, 
Taylor, Win., statement of, . 



. 392 

. 241 

. 387 

. 281 

207, 227 

. 405 

. 285 

127, 285, 286 

177, 182, 186 

125, 414 

. 188 

28 

8, 19, 25, 28, 31 



XCV1 



THE GYPSY MOTH. 



Teaming from infested region, . 

Telea polyphemus, 

Tent caterpillars attacked by warblers, 

caterpillars destroyed by Baltimore oriole, 
caterpillars destroyed by spraying, 
caterpillars killed by arsenate of lead, . 
Terns as insect destroyers, .... 
Territory infested. See Infested region. 
Thaxter, Dr., on vegetable parasites, 
Thelymorpha vertiginosa, 
Theronia melanocephala, 

destroyed by wood pewee, . 
habits of, ... 
Thomixus sp. attacking the gypsy moth, 
Thrush, brown, feeding on the gypsy moth, 

wood, feeding on the gypsy moth, 
Tideman on ravages of the gypsy moth in Kazan 
Time between molts, 

in pupa stage, 

of feeding, 

of hatching, ...... 

record of men's, 

required for emerging, .... 

spent in laying, 

spent in mating, 

spent in spinning, 

Tin, use of, on trees, 

Tiresias serra, 

Titmouse attacking the gypsy moth in Europe, 

attracted by meat, .... 

great, attacking other birds (see chickadee) 
Toad attacking the gypsy moth, . 
Tobacco mixture as an insecticide, 

Tolype velleda, 

Torches, kerosene, for burning caterpillars, 
Tortricids, British, dark color of, 
Tortrix fumifei'ana attacked by Pimpla pedalis, 
Tower, W. L., notes on caterpillars, . 

on predaceous Hymenoptera, 
Towhee bunting, feeding on gypsy moth imagoes, 
Towns and cities from which false alarms have been 

divided into sections, 

efforts concentrated in outlying, . 

infested, citizens from, present at hearings, 

infested, proportionate numbers of gypsy moths 

inner, increase of the moths in, . 

inspected beyond infested area, . 

necessity of inspecting apparently cleared 

worst infested, destruction of eggs in, 
Traffic, clanger from, 

distribution of the gypsy moth by, 



PAGE 

108 
401, 402 
219 
213 
140 
144 
206 



received , 



405 
392 
375 

220, 376 
376 
405 

208, 225 

208, 236 
281 
305 
333 
311 
294 
52 
336 
364 
342 
332 
189 
385 
209, 232, 233 
229 
233 

222, 404 
483 
402 
39 
271 
377 

169, 329 
379 

225, 227 
201 



in, 



50 

53 

84 

99 

92 

198 

80 

69 

109 

102 



INDEX. 



XCVll 



Traffic, ratio of distribution by, . 

study of, .... 

Transportation, a study of the methods and routes of, 

by freight, .... 
Trapping of male moths, results of, 
Traps, caterpillar, 

moth, 

Travel, danger from, to Boston, . 

direction of, from infested centre, 

lines of, .... 

Travelling of young larva?, . 
Treadwell, Professor, experiments on robins, 
Tree creepers attracted to meat, . 
Tree ink, trees banded with, 

pruning, .... 

Trees, alarming condition of, in 1889, 

banded, . 

banded with burlap, 

banded with raupenleim, 

banded with tarred paper, 

banded with tree ink, . 

comparison of yearly work on, 

defoliated by the gypsy moth, 

destroyed by the gypsy moth, 

hollow, treatment of, . 

infested, location of, 

infested, marked with white paint, 

leaf area of, . 

per cent, of pupae in, 

saved by contact insecticides, 

scraping of , . 
Tragus flavatorius, 
Trombidium bulbipes, . 
Trouvelot, Leopold, interview with Prof. N. S. Shaler, 

introduction of the gypsy moth into America by, 

residence in Medford, . 
Tube, paint and creosote, 
Tubercles, larval, . . . , 

retractile, 

Tubeuf, Dr., on disease of nun moth, . 
Turpentine for destroying eggs, . 
Tussock moth destroyed by spraying, 

increase of, due to sparrows, 
Tutt, J. W., on the extermination of the gypsy moth 
Tuttle, Mrs. R., statement of, 
Tyrannus tyrannus, 



in England, 







PAGE 


. 


109 




109 




106 




110 


80 


357 


. 


311 


358 


360 




107 




107 




108 




310 




204 




229 


64, 


128 


. 


172 


. 


33 


126, 


195 


69, 85 


167 




64 






28 






64 




. 92, 93 




57, 85 


23, 70, 


274 


63 


187 




99 






51 






494 






335 






58 






189 






378 






404 






4 






3 






4 






124 






300 


3 


03, 


304 
405 


1 

J 


23, 


416 
140 
235 
270 


11, 16 


, 25 






207 



xcvm 



THE GYPSY MOTH. 



U. 



Uhler, Prof. P. P., description of Podisus serieventris 

determination of Hemiptera by, . 
Unfertilized females, eggs laid by, 
United States Senate, resolve passed by the, 
Urates, presence of, in malpighian vessels of larvae, 
Useful birds, 

insects v. birds, ...... 

Utah, cricket ravages in, 



. 399 
. 400 
290, 365, 367 
83 
. 370 
. 210 
. 240 
. 206 



Y. 

Value of egg-eating birds 229 

Vanessa antiopa, . . l 400, 402 

Variation in size of imago, 338 

Vegetable parasites, 288, 405 

Vehicles inspected by police, 54 

transportation of the gypsy moth by, . . . 39, 102, 103, 107 

Vertebrates, insectivorous, 404 

Vespa consobrina, 378 

germanica, 378 

maculata, 378 

Villages, inspection of, 197 

Vireo, red-eyed, attacking gypsy moth caterpillars, . . 207, 216, 225 

white-eyed, attacking the gypsy moth, 208 

yellow-throated, attacking the gypsy moth, . . 208, 217, 227 

Vitality of dipterous larva?, 386 

of gypsy moth eggs, 279, 291 

of caterpillars, 299, 325 

of predaceous bugs, 393 

Volsk, ravages of the g)'psy moth in, 282 

Voronezh, ravages of the gypsy moth in, 281 



w. 

Wachtl and Kornauth on disease of nun moth, . 
Wadding bands, Klausen's experiments with, . 
"Wakefield, petition presented by selectmen of, . 
Walker, J. J., on the distribution of the gypsy moth, 

Wallace, Mrs. B., statement of, 

Walls, stone, comparison of yearly work on, 
Warbler, black and white, attacking the gypsy moth, 

black-throated green, attacking the gypsy moth, 

chestnut-sided, attacking the gypsy moth, . 

creeping, feeding on the gypsy moth, . 

Maryland yellow-throated, attacking the gypsy moth, 

yellow, attacking the gypsy moth, 
Ward, A. H., suggestions on insecticides by, 
Ware, E. C, directions concerning care of sprayiug machines, 



405 
286 
36 
268 
44 
. 93 
208, 225 
208 
208 
227 
208 
208, 227 
142 
155 



INDEX. 



XC1X 



Warsaw, occurrence of the gypsy moth in, 

Wasps, predaceous, 

Water birds as insect destroyers, 

distribution of the gypsy moth by, 
Wax, grafting, use in pruning trees, . 
Weather, effect of, on the moth, . 



egg destruction hindered by the, 



by, 



influence on assembling, .... 
Webster, Prof. F. M., spraying v. bees, 
Weed, Prof. Clarence M., infested region visited by, 

on feeding habits of the gypsy moth, . 

report of (Appendix D). 
Weijnbergh on parthenogenesis, 
AVeir, J. Jeuner, on the extermination of the gypsy moth in En 
Wellington, Dr. Chas., on Paris green and lime, 
Wellington, J. E., statement of , . 
Weston, S. F., statement of, ... 

Whale-oil soap, use of, 

Wheeler, J. G. , statement of, ... 

White-breasted nuthatch attacking the gypsy moth, 

White-eyed vireo attacking the gypsy moth, 

Wiggin, Mayor, at conference on gypsy moth (Appendix A), 

Wild, Miss Helen T., statement of, . 

Wilkes on occurrence of the gypsy moth in England, 

Williston, Dr. S. W., determination of dipterous parasites 

Winchester, outbreaks of the gypsy moth in, 

petition of selectmen, . 
Wind, distribution of caterpillars by, 

influence of, on assembling, . 
Wingelmuller, C, on flying of female, 
Wings, atrophy of female Orgyin, 

effects of shellac on, 

form of scales of , . 

markings of, . 

not necessary to mating, 

sound producing apparatus on, 

spiny area of, .... 

" Winning" colony, pupation in, 

second brood at, . 
Winter oaks attacked by the gypsy moth, 

pruning, 

Woburn, area of infested woodland in, 

woodland burned at, . 
Wodzicki, Count, gypsy moth ravages on estate of, 
Wood, C. E., observations by, on the yellow-throated vireo, 
Wood, E. W., elected chairman of committee, 
Wooded region, inspection of, 
WoodlandJ^ar^, of, i£fes-„ted, 

birds in infested, . 

burning of, 

colonies found in, . 



PAGE 

283 
378 
206 
98, 105 
177 
84,96 

78 
346 
157 

69 
215 



land 



366 

270 

491 

30 

30, 43 

163, 4S5 

20, 28 

208 

208 

45 

13, 21 

268 

387 

58 

36 

98, 301 

346 

344 

273 

351 

342 

337 

356 

341 

341 

335 

295 

282 

181 

87 

165 

232 

222 

76 

GQ 

87 

223 

165 

70 



!17. 



THE GYPSY MOTH. 



Woodland, area of, defoliated by the gypsy moth, 

extermination of the gypsy moth in, . 

injury done to, by the gypsy moth, 
Woodpeckers attacking the gypsy moth, . 

attracted by meat, . 

eggs scattered by, . 

feeding habits of, . 
Wood pewee attacking parasites, 

attacking the gypsy moth, . 
Woods, explanation of colonies in, 

inspection of, ... 

moth checked in, . 

result of search of, 
Wood thrush attacking the gypsy moth, 

distributing gypsy moth caterpillars, . 
Work, cost of, increased by delayed appropriations, 

delayed by snow storms, .... 

done annually, comparison of , . 

field, advice of Professor Fernald concerning, 

of 1891, . 

of 1892, . 

of 1893, . 

of 1894, . 

of 1895, . 

of four years, summary of, 
World's Columbian exposition, exhibit at, . 
Wounds from pruning, how healed, . 
Wren, house, attacking the gypsy moth, . 

driven away by sparrows, .... 

European, destroying eggs of the gypsy moth, 
Wright, Walter, note on liberation of English sparrows, 



PAGE 

85 
248 
88 
207 
229 
230, 231 
210 
220, 376 
207 
107 
87 
88 
80 
208 
236 
78 
63, 85 
92,93 
57 
45 
62 
68 
72 
83 
91 
200 
177 
208, 227 
234 
232 
234 



Y. 

Yaroschev on ravages of the gypsy moth, ..>... 282 
Yellow-billed cuckoo destroying the gypsy moth, . . . 207, 212 
Yellow-throated vireo attacking gypsy moth caterpillars, . 208, 217, 227 
Yellow warbler attacking the gypsy moth, 208 



z. 



Zinc, arsenate of, experiments with, , 

use of, on trees, . 
Zmiev, ravages of the gypsy moth in, . 



* in §k 



480 
189 
282 




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